It’s basically misanthropy. These people have such low opinion and expectations from humanity that they believe capitalism is perfect, humans are awful. All issues in the world are due to humans being awful.
And any other system, like socialism, would exacerbate the shitty human nature even more.
We have to be THANKFUL capitalism was invented. If it wasn’t for capitalism we’d all be slaver rapists, or something.
As much as I personally enjoy fictional post-apocalyptic wastelands (Mad Max, Fallout, etc.), I do find the whole genre a bit problematic because it often seems to function to reinforce the idea that humans are inherently violent, greedy, and incapable of non-opportunistic cooperation. I've even seen Lemmygrad posters speak as if Mad Max represents a realistic vision of a potential future for humanity.
There is a fair number of people who are operating under the assumption that any and all commerce is capitalism. If you buy something, you must be a capitalist!
It isn't, but that seems to be a very common assumption.