I do agree that the hard left seems to enjoy using "liberal" as an insult, knowing that what most Americans interpret as "liberal" is different than the academic definition they use. It needlessly diverts the conversation and makes them think they're superior.

Saying "shitlib" is even worse. Basically an adhom attack, not acceptable when the other party is being civil and respectful.

On #2 and #3, I don't think that is relevant to the original accusation. Of course they will uphold their own views. But #1 is very valid. Though I wish to see examples of it because I have not.