Socialism is not really an ideology anyone wants to be apart of. I don't understand why someone would want to be a Socialist, of course, if you support Socialism as the stepping stone to Communism that makes more sense, but just being purely a Socialist is weird. Generally, though the abolition of currency, class, and the hierarchy is something I can get behind in a post-scarcity society.
Some people don’t want to buy into the nihilism that life is a rat race, that there is no other option but to eat the other dog, that Capitalism is eternal and inescapable human condition. It’s obviously more detailed then that, but that’s the jist of it.
Your comment is asking why would anyone be a Capitalist in 13
th century Europe anyway, where the Church, the Fiefdom, and the King reigned supreme. Slowly and steadily, it was proved to not be eternal.