Is there an explanation for why westerners who follow an anti reactionary ideology have a loud purist minority?

Maybe a combination of something like the importance placed on forms while neglecting substance, and something like this:

The problem here, in short, is elitism. Unchecked, presumed to have been neutralized in some way by the adoption of a counter-cultural ethos, it festers. The way to solve it, however, is not to shy away from studying or exposing bourgeois propaganda, but to delve even deeper and radicalize our understanding of it.

I think an important distinction to make here is that between the directly oppressed who might just in the earlier stages of class consciousness and class struggle sort of replicate the form through which they are oppressed, and those who are part of the privileged groups but claim to support anti-colonialism, anti-imperialism, etc.

I would also say that due to their often more privileged position, these types, due to their remaining idealism tend to think they have all the answers, and that they know better than others. A sort of western chauvinism which takes its own answers to be the absolutely correct everywhere else. Just because they proclaim, or maybe even truly believe in these causes, they cannot look past their own chauvinism and continue to absolutize their point of view.

Losurdo describes chauvinism, in regards to nationalism and internationalism, but I think his formulation can be extrapolated onto other forms of chauvinism as well:

The repression of national particularities in the name of an abstract ‘internationalism’ facilitates things for a nation intent presenting itself as the embodiment of the universal; and this is precisely what chauvinism—in fact, the most fanatical chauvinism—consists in.

Losurdo also ventures into an analysis of similar phenomena to what you describe and characterizes them as populism which stems from a reductive reading of the theory of class struggle (among other things) which limits it to just oppressed vs oppressor, and tends to lead to putting the oppressed identity on a pedestal without much analysis. He deals with it in chapter 13 of Class Struggle if you want to read it all, which I definitely recommend.

This is a further expression of populism: moral excellence lies with the oppressed who rebel and those who offer help to the oppressed and rebels. But once they have won power, the latter cease to be oppressed and rebels and forfeit their moral excellence. And the one who, by virtue of aiding them, basks in their moral excellence also finds himself in serious difficulties. This is a dialectic already analysed by Hegel in connection with the Christian commandment to aid the poor, which manifestly assumes the permanence of poverty.

Speaking from experience. It’s difficult to accept that you have been lied to your whole life by authority figures. As aristocratic labor, I’m invested in keeping the system going, but know that ultimately it is the problem. Creating cognitive dissonance that can’t be resolved. This makes us lash out.

A mixture of all of your hypotheses are correct.

The shortest way I can possibly explain it: online “leftist” (massive, undefinable group which is one issue) culture(s) are just that… online.

For all practical means they do not exist in the real world. People trying to purge all white males just don’t “actually” exist. I really hope that doesn’t need further elaboration, since it’s one of the pillars of white nationalism in the US/EU that these types DO exist and are actively purging white people. The few who do exist have no power and to my offhand knowledge have never once acted with whatever power they might have ie some localized genocide of whites in South Africa. That never happened, despite fearmongering from apartheid-beneficiaries that it would definitely happen. Slavers in the US feared abolition for similar reasons. It’s really important to realize that these groups are tiny and powerless in order for you (and me) to ignore them or limit engagement to something productive… which is usually non-engagement, not even to mock.

On some level obviously you’re right to have a negative reaction to a group of people who never met you wanting you to die, be enslaved, whatever. But you have to also realize in that same moment of reactionary-tendency that… they don’t matter. They don’t have power. If it makes you feel better (worse…) the CIA/FBI wants you dead or in some way subdued as well. The difference is they have the legitimacy and backing of the United States federal government. You tell me who is a bigger concern and threat.

It’s ultimately the rantings and failings of people who are being or have been historically treated less than human by the machinery of capitalism. They either lack proper understanding or education or, more bleakly, they do know and have all the knowledge but they see the world for what it is…a capitalist hellscape unlikely to change anytime soon. They can also see this white-created world of exploitation and drive towards ever more consumption destroying the world and they see who chiefly benefits from this world… the descendants of those whites. Of course it’s wrong to profile people based upon skin color, etc., but put in their shoes, I find it hard to blame them for the negative perception of ALL white people in the the “first world” and especially people whom would claim to be their liberators their “torch carriers” if you will who will only listen with one ear and speak over them half way to tell them their concerns are not justified and they’re just being anti-white racists. We cannot ever experience in this life the experiences that leads people to reactionary type mindsets. So it’s worth acknowledging you somewhat understand WHY they are how they are and the only way you’re ever going to undo hatred towards you is to be better than your ancestors probably were. I really don’t know what else to say here besides like don’t let others who are misled (or whatever wording) pull you from your own journey or spoil your own knowledge of things. Be sure of your values, your morals, your understanding of the world. Challenge yourself and let others challenge you, too, but root yourself in justifiable ideals. Probably comes off corny, but whatever, when you have a anti-colonial, anti-capitalism, pro-emancipatory stance as your core you can encounter new ideas, different types of people and cultures, you can incorporate parts of them into your own being and remove unwanted ones as well. As long as you’re always in the mindset of morality, “the golden rule,” and you know what that world looks like… you can’t go wrong.

(I realize this comes off like religious stuff, obviously everything is open to change when more knowledge is gained, but I really do believe there must be certain pillars to your personal morality. Doesn’t have to be based in religion, just a conscious memory you keep that you would like others to treat you well and you will treat others as you wish to be treated. I kind of don’t think you end up in realm of leftist thought without having that rooted deeply inside you. Reactionary tendencies are probably your subconscious (or whatever, not a fucking psychologist here) rebelling against your actions going against that core pillar and the internal struggle to resolve that contradiction between deeply held morals and opposing actions. Way too big brain on a Saturday).

Probably rambled a lot there, but whatever. Just be cool, and don’t let others tear you from the correct path.

“Everyone else must bow down to me and insert group because we are the true next Lenin and we will lead the revolution using our perfect ideals. So everyone else must listen to us.”

I haven't come across users like this before, it could be a combination of all of the factors you listed at the bottom. I would be more inclined to believe these users are people who are possibly new to a movement and don't fully understand what they're taking part in.

I can only really speak to the general communism umbrella but lack of theory leads to weird contradictions like the one's you have pointed out.

I'm not quite sure what you mean? Can you elaborate a little bit? These groups you've mentioned aren't really related in any way and aren't really socialists.

Groups like TERFs are reactionary, co-opting socialist rhetoric, as openly reactionary rhetoric tends to turn people away, so they just lie about their true intentions and motivations, pretend to care about people when all they want to do is spread hate. A certain group of "national socialists" in Germany in the first half of the 20th century are probably the best example of these sorts of hateful people using empty, vaguely socialist sounding terms to get broader appeal.

As for groups like Afrocentrists, it seems to be mainly something to do with them unfortunately just lacking proper historical knowledge, they know the way history is taught in schools is wrong (i.e. Eurocentrism) but lack the knowledge to understand why, so they end up concocting elaborate conspiracy theories that just reframe Eurocentrism instead of actually learning about true African history. They don't understand that the alternative to "All the important stuff in history happened in Europe" isn't to just replace Europe with Africa, but rather to reframe history into understanding that all history is valid and worth studying and isn't some kind of competition.

For a more general sort of analysis of people who are very..."militant" about their beliefs, it is often because they feel morally superior, and may feel a desire to "save" others, not realizing that proselyting about veganism or communism or whatever just turns people away.

As for psyops, that is possibly true for some. A group who have very strict and rigid ideas and are very hostile to outsiders won't ever convince the masses of the benefits of socialism, and so make for excellent controlled opposition.

The more extreme a person's views are, the more likely they are to talk about them. This is the same of any belief, any alignment.

Don't over think it.