It is the same argument, it's laughable you can't see it. The very same type of argument, except that one was already deemed illegal long ago so you can't see the similarities. Let me help you using your own sentence. Imagine this was a thread on steroids and whether they should be used in MMA or not. This is your argument. "Their opponents have exactly the same opportunity to get stronger using steroids. Most of them do and what you end up with is an even fight. If their opponent chooses not to - that is their choice." Steroids are illegal because of their negative health repercussions and they give an unfair advantage to one person if the other isn't using them. The dehydration issue has negative health consequences, and gives an unfair advantage if someone isn't doing it. Exact same issue. In IFBB competition, they don't test for steroids and so many body builders use them, nearly all. But there are many who don't because they don't want to deal with the side affects to their health. So, those who take them have an advantage over those who don't. It's just like you are saying the "natural" body builders should start using juice since it's part of the game.