I don't think Liberal means what you think it means. But that aside, if you study fascism, or just read through the short list from Eco about fascism, it would be very hard to deny that the right wing in the United States dipping not just it's toes, but wading into the seas of fascism.
Umberto Eco (1932 – 2016) was an Italian philosopher, cultural critic, novelist, and political and social commentator. He grew up in Italy during the years of Mussolini. In June of 1995 he published an article in the New York Review of Books about fascism, a subject he knew well. link
The cult of tradition. This is the belief that the truth is already known once and for all. Fascists believe there is no need to advance in learning.
The rejection of modernism. Fascists reject the Enlightenment and its evidence-based rationality.
The cult of action for action’s sake. Fascist leaders act impulsively, without thinking or planning ahead.
No analytical criticism. Fascists ignore nuance and see any disagreement as treasonous.
Fear of difference. Fascists fear diversity. Thus they are racist by definition.
Appeal to a frustrated middle class. An economically frustrated and/or politically marginalized middle class is easy to stir to anger.
Obsession with a plot. Because the followers must be made to feel besieged, an internal “enemy” is provided: Immigrants, Muslims, Hispanics, Blacks. (Historically the Jews were often made to be “the enemy.”)
Anti-elitism. The followers are made to feel humiliated by the wealth and strength of the educated “elite.” This is used to create resentment.
Pacifism is trafficking with the enemy. Fascists believe that life is permanent warfare. Therefore a desire for peace is treasonous.
Contempt for the weak. A fascist leader despises his underlings, who in turn despise those under them. They all either mock or ignore the poor, the sick, and the disabled.
The cult of heroism. The Fascist is eager to die a hero’s death. In his impatience, he frequently sends other people to their deaths.
Machismo. Fascists show disdain for women, disregard for chastity, and condemnation of homosexuality.
Selective populism. Under fascism, the “voice of the people” is not the democratic majority, but only the voices of those who support the leader.
Ur-fascism speaks Newspeak. Just as in Orwell’s 1984, Fascists use an impoverished vocabulary and an elementary syntax to limit complex and critical reasoning.
I don’t call people who disagree with me fascists. Disagreement is healthy and important. The world would be boring as fuck if we all agreed on everything.
I call people who lick the boots on their own necks fascists. I call people who celebrate fascist ideals fascists. I call people who vote for fascist policies and candidates fascists.
It’s easy to not be called a fascist by not being one.
If it walks like a duck and quacks like a duck. Chances are it's probably a duck.
That said they may be taking it as a sign of the other person's larger ideology. For example if they have a strong anti immigration stance they might come to the conclusion that the person is racist.
There's sometimes the mentality if you give this person an inch they'll run with it so they may say it to stop things from derailing
There's also a ton of dog whistles the alt right use. Remember when the milk emoji was used on Twitter? What about the okay sign? Hawaiian shirts?
Because they're socially liberal, opposed to most forms of social conservatism. The term rose to prominence in its current US meaning in the 1920s and 30s.
It was first used (in this sense) to identify a more moderate economic approach as compared to movements that were perceived as more radical like progressivism, socialism, communism, etc.
"Fascists" are people who have particular beliefs, and participate in politics in a particular way.
Those beliefs and practices disagree with a lot of beliefs and practices that are called "liberal".
(Mind you, "liberal" is a word that's used to mean a lot of different things. I'm okay with calling myself a "liberal", because people understand "liberal" a lot better than "progressive libertarian centrist" or "non-communist anti-fascist" or a lot of other things I could call myself..)
But if you happen to "disagree with liberals" in the particular ways that fascists "disagree with liberals" ... then you are in fact a fascist.
I don't think it's useful to categorize liberals in this case, so I'm going to answer the question: Why do [some people] call those who disagree with them fascists
Some people use fascist or Hitler or the holocaust (or the atomic bomb or...) as a generic evil, as per Godwin's law or reducto ad Hitlerum This isn't specific to fascist or WWII tropes, as the term terrorist became quickly misused by right wing interests in the US against journalists and others who sought to serve as a check on the misuse of power by the US federal government, and currently, the term groomer (typically used to talk about people lure children to victimize them) is being applied to LGBT+ people in general by right wing pundits and even some government officials.
However, as Mike Godwin noted, there are actual fascist movements gaining popularity in the United States, Europe and elsewhere. The Republican Party, when it was taken over by Donald Trump during the 2015-2016 Republican Presidential Primary rapidly shifted in lockstep with the transnational white power movement, which has a lot of intersection with MAGA, with the Alt-Right, and with the white Christian Nationalist movement that has been guiding the Republican party since the 1970s, and has been putting Federalist Society jurists on the US Supreme Court (thanks to the influence and mission of Leonard Leo) with the direct intent of retracting civil rights, first from marginalized groups and eventually from the entire US public.
So at this point, a lot more people have an awareness of the threat of fascism, and see all efforts to preserve hierarchy in the US, to withhold human civil rights or to target marginalized demographics as serving to accelerate the fascist takeover of the United States, whether or not the person engaging in the behavior is directly aware that this is the end result. So even if, say, a given person is an OG fiscal-responsibility conservative, by voting for the Republican party (or even failing to vote for the Democratic party) he serves the fascist takeover, the neutering of elections in the US and the rise of authoritarianism. Most MAGAs, for example, are useful idiots, sometimes having socialist ideals, yet voting for Trump-aligned Republicans out of fear of the menaces they insist plague the US (often, imaginary bogeymen, not backed by facts or statistics).
Could ask the same thing about all the constitutional conservative “#maga #anti-fascist” accounts on Twitter. Go police your own party’s nonsense first.
Because they're unable to distinguish between a state that enforces human rights and a state that enforces human rights violations. To them, the state doing things is always fascist.