For instance, he kills almost everyone in the flood. Even newborn babies with "original sin", which is a made-up fault.
Also, judging is fine. Violence and cruelty are not.
Well it is said that the thoughts of people was always and only evil so... But there is more to that which is described in the book of Enoch.
I'm not going to read the book of Enoch to find out what you mean with this tangent about thoughts being evil. I would like it if you provided a concrete example.
Long story short they were not human AKA homosapian sapian. They were half human half something else. They have oppressed and almost destroyed humanity.