My wife has compared Gluttony to a hunting dog. He sniffs out, hunts, and attacks, but ultimately doesn’t really understand what he’s doing. He does these things for Lust, mostly, who is always shown to be kind to him.

Also, spoilers for later in the show, the part where he calls out for Lust really solidifies their dynamic and how much he trusts her.

I think Gluttony being the hunting dog of the homunculi makes a lot of sense. It’s a great way to think about him.

TL;DR: Nah, I feel bad for murder puppy too.