@Ken,
The answer is simple. There are other creatures that eat slugs and when it eats a slug killed with those nasty chemical baits, you in turn kill that animal. Is it worth it? This doesn't just apply to slugs. It applies to anything killed with a poison. Unless you go out there and scoop up everything you have killed with a poison, you run the risk of killing something else that will eat said poisoned something. Poisoned baits are NOT the only way to get rid of slugs.
Oh, and yes, I do hug trees. All gardeners should... don't you think?
