Except that the creature argues on its own behalf. It communicates. It lies about the crewman it murdered and comes up with a whole fake story about plant poisoning. It picks favorites that it won't kill. It kills Crater, not out of a need for food, but because he says he can ID it creating a motive for plain old murder. Buffalos don't kill people to hide their secrets. Heck, Memory Alpha says the final script attributes the ruins to the creatures. I don't want to keep going around in circles, so, latch on to the buffalo thing if you want, but literally everything in the story contradicts you completely.