Why do people say that some rappers are ex-criminals?

I mean, what's so bad about selling illegal drugs or pimping? People die from abusing legal drugs all the time (last famous victim is Derek Boogaard) and people don't comdemn those who sell them legally. Hustlers are just entrepreneurs and it's not their fault that the government has decided that certain drugs should be illegal. The same with pimping, it's just a business. It's legal in many parts of the world, there's nothing criminal about it.