Not in a court of law, but I have been watching his sad, slow descent as a person over the last 10 years so it unfortunately would not surprise me anymore. It's one thing to be a jerk to people but he has crossed an uncrossable line.
From everything I am aware of, he was not doing this in the '90s or the 2000s. In the last 10 years though, things seem to have been completely devolving. Nasty remarks on and off the stage, combative behavior, rambling diatribes that are supposed to be songs, and now this... I'm wondering if he has developed some sort of unchecked mental disorder.