We have had violence for millions of years.
The animals do become violent to protect themselves, and for food, however, the chimps are forming gangs and going after and ganging up on some unfortunate one that they do not like.
Are they becoming humanized on their own?
This is something that has been developing in the wild recently, you figure.
I do believe that it is connected with crowded areas, but it is no different than other areas that were not so crowded as well.
Violence is everywhere.