Many idealists enjoy the passive role of being a noble martyr(less work), but leftists make plenty of terrible decisions, not the least being spending so much time and effort trying to prove they're differenti from people with the exact same ideology and principles as themselves.

Liberals and leftists both make memes, and the meme makers are useless people.

Liberals and leftists both go to protests, call up their senators, and enact change in their communities, and the action-takers are useful people.