"Creature"? Let's use another word, like "animal" or "living being", maybe.
Also, gorillas have behavioral patterns, logical thoughts and emotions very close to that of a human being, so it's a shame that no one expected something other than an unexpected bloody dinner scene from such a "creature".
I'm going to play devil's advocate for a moment. Yes. Gorillas and many other primates share similar traits to us. And only expecting violence from these animals is wrong. But it still is a wild animal. We can predict their behaviors but we aren't always right. So it's best to be on the defense than being utterly vulnerable.
Also, gorillas have behavioral patterns, logical thoughts and emotions very close to that of a human being, so it's a shame that no one expected something other than an unexpected bloody dinner scene from such a "creature".