That psychological aspect usually plays some role in transitionary theories for certain brands of communism, especially anti-statist brands. Although nailing down exactly what role it's supposed to play is usually pretty difficult, it's fair to say that the answer to your question would -- for a lot of anarcho-communists -- boil down to something related to these psychological theories.
This post may sound uncharitable to those communists. And I don't agree with their theories. But I also think that their work contributes something very important to discussion of fringe political theory:
Flipping a psychological switch in the minds of the masses is an absolute pre-requisite for most anarchist theories.
IMO that includes anarcho-capitalism. The communists at least recognized this way earlier than everyone else and are very careful about identifying psychological theories that match well with their sociological theories.
We can argue whether psychological switch-flipping is a realistic expectation -- I'd argue not. But any time I read political theory, I try to identify where the author invokes a form of switch-flipping. 99% of the time the author just makes overly charitable assumptions about human psychology -- that's usually the case in mainstream politics. Communists sometimes have some Freudian psycho-analytical flavored theory. Anarcho-communists like Molyneux prefer weird pseudo-logical reasoning about moral axioms.
Implicit assumptions of switch-flipping show up in mainstream politics as well (IMO "drain the swamp" and "black lives matter" both make implicit assumptions about switch-flipping that under-estimate the stubbornness and importance of human psychology...)
I would also note that sometimes, people operating off a 'psychologist' basis like you've identified, misunderstand the critiques of others as being also 'psychologist'. For example, the Hayekian critique of central economic planning is often characterized as a psychological argument that "people are naturally selfish and greedy". Thus, if you can get them to stop being so selfish, the objection is overcome. However, what the critique is actually about is inherent limits to knowledge and information, which would apply regardless of psychology.
No, usually the psychological arguments are needed to hand-wave away crucial but obvious problems.
> Well, that's a big weakness of these theories
No, it's not. It's perhaps their most important insight.
I mean, IMO they're wrong, but the insight about the need for a psychological aspect is important and correct.
Libertarians and especially anarcho-capitalists need similar psychological arguments (the fact that they often hand-wave over this need not-withstanding).
Except maybe there's a system for which that's really true, and you and I prevent us from ever getting to that system because we reject arguments like this on the basis of form? Oh dear ;-)
No it does not.
(Most) Anarcho-Capitalism assumes humans as they are now.
It uses the same analysis as do political scientists and economics use now to model systems.
Most AnCap explicitly reject "Socialist Man"-type stuff.
No, most anarcho-capitalism that is analytical (rather than holding anarcho-capitalism directly as a first principal) relies on outdated idealistic models of humanity.
> It uses the same analysis as do political scientists and economics use now to model systems.
In that, despite its well known flaws, the rational choice model is still frequently used (either as a tolerable simplification in some contexts, or simply from inertia in others) in both political science and economics, this is true. OTOH, it remains an known-to-be-false idealized model.
You are simply arguing against most political science and micro economics. I use those disciplines to explain why I think Anarcho-Capitalism makes sense.
If you don't except these then I can not convince you of anything, not even that dictatorship is bad or anything else. There is no point arguing.
I fail to see the logical inconsistency.