Koko was not a chimp. Chimps actually do wage war against other chimps, even killing them.
Gorillas like Koko don’t- they may have territorial displays but they don’t have the vindictive aggression of chimpanzees. Apes do seem to have better grasp of language, are able to assemble signed words together in sensible ways rather than just repeating the same learned motions.
I wonder how Bubbles is doing...
https://people.com/celebrity/whatever-happened-to-michael-jacksons-chimp-bubbles/