The evidence seems clear that PEDs do enhance performance, at least for a short time. Long term health damage has been shown for at least some PEDs. So the situation is simple, if you do not ban PEDs, they become essentially mandatory. If everyone is taking them, there is no net competitive edge, but the players all get extra health risks. Here's another way to look at it, suppose you have a son who likes baseball and shows some talent for it. Would you want him to be taking these drugs? Would you say to him, "To be really good, you need hard work, dedication and a concoction of drugs. Start taking them now."