I guess in some way, animals ARE better people than people xD
Most animals that aren't good learned from humans. Like dogs.
Also, people that get hurt by animals, normally did something wrong. Like petted them in a wrong spot or kicked them or stuff like that.
But the "killing for fun"-gene seems to be in most species that eat meat or fish. Don't think a cow would kill for fun
The only thing is how to avoid all the possible triggers for those that have the gene.
That's what I don't get with humans. Gay couples can be like gay penguins and give kids that have been abandoned a good home. But they still have to go through so much to adopt a child. Much more than a "normal" couple...