Once someone drags your name through the mud in public, it's well past the point of having a private chat. His behavior isn't a huge red flag in the slightest; he's responding to what's essentially a public attack of his character. Responding to something like that publicly when it's already a public situation isn't a form of aggression.

You are projecting WAY too much of your own bias and opinion into what was simply a response. It's telling that you're suggesting he needs to have social maturity when the allegations levied against him are pretty unsubstantiated- see the "evidence" of him retweeting an article discussing free speech concerns on college campuses.

Are you genuinely so obtuse as to scorn a man who's attempting to merely respond to being accused of something?