Tied into this, I think there's also an element of liberals expecting a certain bleeding heart morality to the left that they believe paralyzes. They don't want solutions out of the left, they want to have socio-political catharsis through the veneer of left politics. So some might cry: "what's happening in Yemen is so sad my heart goes out for them", yet ultimately decide that the 'rational' amoral realpolitik demands the US play this game with the Saudis else things could be hypothetically worse. 'Ignore the heart, choose the mind' type attitude when it comes to the "real". So' coming up against leftists that are less interested in playing the bleeding heart or (merely) stroking their own ego by pointing to moral superiority forces one to re-evaluate either what they consider to be left or the stated values/goals of the leftist challenging this framework.

Hopefully this made sense, I'm not running on a lot of sleep lmao.