Rose broke the letter and spirit of the rules, so he stays out of baseball. It's quite easy to defend that position. But with Bonds et. al., what is MLB to do? I don't think the use of steroids or other performance enhancing drugs is specifically prohibited in the rules. It may be now, but the horse is out of the barn, so to speak. MLB has a history of giving people with cocaine habits a second (or third, or fourth) chance, but should that stance be the same for performance enhancers?
I think the use of steroids is cheating, but if MLB never specified it, there's nothing they can do.