Cognitive dissonance for one. They understand their own condition as a poor and exploited person living in America, but they hear sensational tales of child labor, gulags, lack of free speech, lack of religious freedom, etc. They hear all of that and conclude for as bad as it is in America, at least they can go to church on Sunday or openly talk about being an anarchist on their blog.

It's why you'll sometimes hear the term red fascism thrown around, the concept being socialist countries are just a trick and actually a worse form of capitalism than normal liberal capitalism.

I think it's kind of like how we sometimes hate the democrats more than the Republicans, because at least conservatives are honest about how evil they are. The democrats are posing as being more progressive than the alternative. For the folk I know, socialist countries are just posing as socialist, which is dishonest to them so that's somehow worse.