DDoSing (read before you delete i'm not gonna ddos anyone)

Yes. It's only karma. In the eyes of the law, you're both guilty, but he was provoked, and did a lot of damage and affected multiple people. (Not damage, but... you can claim that if it ever escalates to legal cases!)

Also, think of it this way. You can TRY to be a good person and NOT DDoS him, but if you don't, someone else who was affected by him will.