@NickFun,
The thing is that if you legalize PEDs then you force everyone to start doing them if you want to be competitive. You might say that it's already happening right now but there's a large percentage of clean players in the game today, or at least I believe so.
If the league legalizes PEDs then the league acknowledges that it's a risk that pro players will have to take if they are to play professionally, just like footballers or skateboarders know they have a high risk of injury when they perform.