Not all of them have, or they chose not to hunt, just to fight when needed. Still, some of them have chosen to fight, and I'd rather help them then see them killed.
I doubt he'll listen. Clary tried reasoning with him, he called her a child. Kendra responded, he didn't answer. Though maybe, I don't know. He seems very set in his way, and if that keeps up, I won't put everyone here in danger of his crazy mind powers.