You have to consider
the fact that these pros have millions to spend and so they get teh best qualitiy steorids and have doctors watching over them daily, so they are able to juice with minimal health risk - although im sure the risks are still there.
A teenager or minor league polayer doesnt have these advantages and will hurt his health trying to imitate the pros. But I guess you can argue that it is their own freewill and they dont have to take those actions.
Apparantly there is much for pitchers to gain from steroids, lucky guys.