I think there is overwhelming public interest that such a thing be illegal.
By the way, he wasn't going around euthanizing stray cats, he was taking cats from people's yards and killing them. So, to believe we shouldn't have laws against it at all, is to believe we shouldn't have laws protecting private property.
I was attempting to point out that there is a significant number of people that are all in favor of animal cruelty, and they come in all political and religious stripes.