To be fair, most animals don't allow multiple males to lead the herd/pack/whatever, so it's harder for them to form an attack troupe like humans or chimps do. Yes, there are exceptions, but when those packs encounter another pack it's just as vicious a battle. And they will gang up on a lone intruder as well.
I don't think humans or chimps are as "special" as a lot of people would like to believe them to be. We're just tool-using animals at the root of it all.