Well that's the problem with moral laws, who gets to say what is good and what is bad, and based on what belief system? Everybody have their own religion and its not for the government to push one down every one's throat. I like to eat seafood and pork, thank you, I don't care about anyone else's moral laws on that matter. Laws should be based on reason.
As for you example, you blame gambling while you should be blaming parental negligence. If parents were feeding their kids with bacon and chocolate all day and the kids were obese, would you blame and criminalize the food or blame parental negligence?
It's not a god idea to restrict everyone's freedom for the sake of protecting some excessive people against themselves.