Why shouldn't we ban tobacco?

freedom of speech is a massive argument. Who are we to say that people can't smoke. I personally am not a smoker, but have many friends that are and have tried it on different occasions. Although it does harm your body, many people argue that if you live in a true democracy you should be able to do what you want, and since tobbaco smoking is such a tradition across the world, and has no effects like drugs, there is no reason it should be made illegal.