Well, veggies aren't bad for you. Sky-diving isn't necessarily bad for you unless you land in the middle of traffic. . There are a lot of things you can do that won't kill you/isn't bad for you, but you're not looking for them because you're too into your drugs to even care.
Yes, that's if you eat too much of it. Samll quantities aren't bad. However, a small quantity of drugs are. If you didn't get addicted after a little bit, I wouldn't think of it as bad. But since you get addicted and continue to smoke it. .