Why is he so angry at me?

We're over, we never dated but he wanted me. He faked relationships, hangs out with his ex a lot (its one of the reasons I left). I am making fun of her and insulting her on twitter because 4 mnths ago he advised the police on me for insulting him and his friends (I didnt contact him but i did this cuz he stole my work and did the faking), and said never to message him again. He kept on stalking me in the 4 mnths, he did nude photography something i hinted while we were talking. Why is he so angry when i insulted her on twitter and said im looking for a bf of my own? He's furious.