Do you really see no difference there?
Well not so very much. Chimps aren't as intelligent as people, but they do display a large variance in behaviors, one to another, as do humans. There are some places I either won't go at all, or will only go armed, but that doesn't mean I don't have sympathy for the folks who live there, nor does it mean I have no sympathy for all people.
As with all animals, you have to treat with them based on some kind of understanding of their behaviors. You can't apply human standards, especially not those appropriate in American society, to chimps. We are supposed to be the intelligent ones after all.
In the case at hand it was human error that allowed the aggressive young chimps (Males, IIRC) who tend to be very territorial, to have access to the humans who were coming to visit the chimp they had raised. That chimp I have a lot of sympathy for, because he or she was not raised as a chimp, but rather as a human. If they gave it up before it got too very old, that might not be so bad, because the differences between baby humans, baby gorillas, and baby chimps are less than the comparable difference between adults of those three species. The folks who had raised the chimp didn't expect any other chimps to be around, so they weren't in the proper frame of mind for handling those aggressive/territorial males, assuming they would ever have had it, which is questionable considering they undertook to raise a chimp beyond just the early "rescue" phase, say through weaning or eruption of teeth.