Yeah, that’s a good analogy. They’re people who emphasise idealism and perfectionism rather than messy, imperfect real world results. They tend to decry existing or past socialist projects for not being “pure” enough and for having issues and problems, like any nation would.

It’s quite common in western leftist spaces as it is a way to be “socialist” without actually needing to unlearn a bunch of lies about socialist nations taught to people from a young age.

We mock them because they ultimately spend all their time “planning” a “perfect” revolution that will never come to pass, as if they actually tried to put their ideas into practice, they would meet messy reality and no longer have everything be perfect. So they claim to be against the capitalist status quo while doing nothing to actually try and change it. They’re as old as communism itself. A core idea of communist thought is “materialism” as opposed to “idealism.” When our ideas conflict with reality, our ideas need to change to match reality. Ultras refuse to do this in order to keep their ideals “pure.”

Sorry for the semi-lecture, especially if some of it is stuff you already know.