Because they’re slightly annoyed by capitalism cutting into their own lives, usually just healthcare and education. Maybe violence/crime and homeless being visibly part of their communities/media, too. Maybe social depression and consumer goods becoming increasingly junk.

They have a handful of really specific issues (you know which ones) and they will not budge an inch left of that. They pick up the socialist rhetoric because that’s where the energy’s at for tackling social injustices on social media, but it’s just tidbits of rhetoric, they not going to actually study marxism or take anything to heart.