Whats really so bad about tobacco?

Whats really so bad about tobacco?
I dont smoke, but i really find it more annoying when people are drunk or high then when they are smoking. And as a practical example, my health teacher always told us that tobacco was the most dangerous "drug" because it is legal, but I personally think that LSD and PCP are way worse. So whats with all these politicians calling for pot to be legal and tobacco to be illegal. If people want to smoke tobacco whats so bad about that?