All it takes is one person to break trust, and lie about it. "You must do this for the motherland/community/people" etc.
It can be a good thing if the imperative originates from an honest person, but it can be very bad if it originates from a dishonest one or from a collective misunderstanding.
Capitalism is powerful in its short-mid term practical effectiveness, but has a kind of slow, long-term slide into brittleness and catastrophe. Socially, it's poor at meeting the underlying needs of people, and instead stuffs people with distractions, short term thinking, etc - which ultimately breaks it.
Communism is great at getting people on-board - it's hard to argue against from an emotional standpoint, because it keys in on deeper instincts that people have - ungrounded, but deeply important instincts. Unfortunately, it has the nasty tendency to go off the talks pretty damned quickly, so all implementations of it end up being 'pseudocommum'.
To be honest, I think communism has great ideals, but I think the practical reality of achieving it is incredibly unlikely, for this reasons I've stated, and others.
However, I think the ideals of it, and even moreso the underlying instincts that it keys in on are deeply important. But they cannot be achieved while sacrificing the individual for collective interests, as communism trends towards, nor by sacrificing collective for individual (or individual entity) interests, as would capitalism.
I believe that collectives that have a foundational focus on individual sovereignty are the way forward.
I think we're more capable than that, it's just that we're not putting in the groundwork.
Revolutionary communism fails because it doesn't level the wealth (and by extension power) inequality that exists under a capitalist system. This means that following the revolution, wealth and political power rapidly reconsolidate, and now you have a wealthy ruling class directing and backed by a corrupted state apparatus... Overnight autocracy.
If you transition via social democracy, eliminating the democracy-breaking wealth imbalance while setting up a robust welfare state that accommodates peoples' basic needs, there's less ability and less motivation to collapse into autocracy, and there will be more pushback from the populace against it because they have better lives, and more enfranchisement than ever.
If the collapse of communism into hellish autocracy is inevitable, you should be fighting it. If communism requires meaningful sacrifice for the bulk of the population that leaves them worse off, you should be fighting it. There's no point to any of this if everyone is worse off - I fight for communism because I want a better, freer, more prosperous society. I'm not sure I agree with the long-term focus on small sovereign collectives, because they'll naturally lead to commerce and comodification, then capitalist wealth and power consolidation without oversight at either the individual or collective level, but whatever sees us all better off.
Not just small sovereign collectives, but any collective (including the government). The key is for the collective, overall, to sustain the rights of any entity that is a part of it. That means sovereignty for all organizations, and sovereignty for each individual. But, that sovereignty ends at the boundary of another sovereign entity.
This isn't just s system of governance, it's a system of morality as well. You can do anything you want, but once it starts impacting others, you begin losing rights. Effectively, if you cannot come to an explicit consensus, implicit consensus is permitted. There are notable grey areas - and since consensus cannot be achieved there, they should be left to social involvement, or to diversity, to handle.
In history, the most egregious actions are those where collectives impose upon individual will, and vice versa. Establishing sovereignty rights is a moral foundation that can, to significant degree, mitigate that.