I would posit that aggression is generally unwarranted. I would consider aggression to be the non healthy alternative to, say, being matter of fact, blunt, terse, and other such ways of giving negative feedback without directly attacking the person.

I'm sure there's no perfect dividing line between non-aggressive/aggressive. But it's generally clear when something is nearer the extremes.

"Alice, that's completely wrong because X, this code needs to be rewritten from scratch following principle Y." "Bob, what is this retarded shit? You stupid fool, go RTFM and do it again."