Chimpanzees are eukaryotes, animals, vertebrates, mammals, monkeys, AND apes. They don't give up being monkeys just because there's a better way to categorize them. Now I'm that guy, give me your crown.
Chimps don't do this much (if at all) in the wild. Goodall's observation of chimp warfare was the result of her team introducing an economic system into the chimp community by giving them a scheduled, finite number of bananas at a specific location so they would be easier to observe. Without artificially imposed scarcity, chimps tend to be peaceful and cooperative. Probably just like us.