Was he critiquing HER as a human being or was he challenging her policies? There's a big difference. I know that some people were yelling at her for talking about her sexual assault - that is pure right wing nonsense and people who claim to be left of center and then piss and moan about her talking about her sexual abuse are, to me, not left wing at all, no matter what else they say in public.
Policy debate regarding AOC is never off limits, right? I mean, she can't always be right about things. It's ok to challenge various political statements she makes. But when attacks become personal or people complain about her abuse testimony, then I would say that all their claims to be "left" leaning are B.S.