The issue surrounding PED use in this instance isn't only the harm done to players taking them. It is the fact that it doesn't create a level playing field and thus is tantamount to cheating. If a player gets injured that is par for the course - they have a reasonable expectation that injury may occur. They also have a reasonable expectation that when they take the field everyone is playing under the same rules. Allowing PEDs is just the same as allowing one team to run 40 meters before they bounce the ball while the other remaining 17 teams have to bounce it every 15 steps.
by wada's estimation only around 2% of dopers get caught, hence the current system doesn't provide a level playing field. perversely if you allowed doping everyone would be taking them and you would have a level playing field.
there's probably better arguments than the level playing field angle.