This is professional sports, people. Taking drugs to build up your body makes as much sense to me in professional sports as a stripper getting implants.
Maybe the Olympics has set the tone for this - the Olympics' charter being to bring together the best amateur athletes. One mark of an amateur is they don't resort to drugs or surgery to increase their chances of winning. Professional sports does not (and IMHO should not) have that limitation.
Just by way of example, it's routine in most professional sports to administer a cortisone shot to an injured player to get them back in the game. This is not allowed in the Olympics. Nor should it be. But don't get me started on that, because I don't think "retired" professional athletes should be allowed in the Olympics, either. The "Dream Team" in Olympic basketball makes me sick.
But that's a story for another day.