Because people want to buy it. Stuff doesn't have to be outlawed just because a few people don't like it. In case you hadn't heard, it's supposed to be a free country.
I used to chew. It helped me quit smoking, but I never heard anything caught from chewing tobacco. I think someone is pulling your leg or dont want you to chew. Mike
Smokeless tobacco—such as chewing tobacco—can deliver more nicotine than cigarettes and contains some 25 cancer-causing toxins that increase the user’s risk of developing cancer of the throat and mouth.