The Red Scare is still working it’s magic I see. I don’t think many people think that communism is the perfect system. Even the ones who support it. It’s just that after living in a capitalist hellhole our whole lives and watching the world burn, some of those ideas start to look like they are worth trying.
Star Trek is a good example of what the endgame of communism is supposed to look like. It’s just the process of getting there that is hard to figure out.
Capitalism is better than feudalism, yes. The problem is that Capitalism inevitably gets to the point where it is more detrimental to the population as a whole than it is beneficial (Global Warming, Wealth inequality, power imbalances, etc.), and that point is now.
Capitalism did bring us many advancements, but we have outgrown it. Just because it did good things at some point doesn’t mean that there isn’t something better. We should all be striving towards better as a species, but we aren’t.