I'd say it's mostly due to uncritically listening to whatever they are told and being part of a more-privileged portion of society that is subjected to less systemic violence.

Sure, some people DO just hold on obsessively to the idea that one day they will truly "make it big," but it seems to me that many liberals are wandering around perpetually lost as to how to address their complaints about society. Once they become exposed to compelling evidence and logic that explains the contradictions they've been confounded by, they'll slowly start asking more questions beginning with "why?"

After that, it's just a matter of time before thinking, "what is to be done?" Maybe I put too much faith in humanity, but I believe most people want an egalitarian society but lack experience with critical thinking and have never had any exposure to the foundational theory exploring how to accomplish this goal.