Why? Im playing devils advocate here btw. Whats the difference between banned substances and pre workout or vitamins? Remember thc was (is?) A banned substance. So if you smoke weed are you a cheater?
I guess they are banned for a reason - i.e. they are seen to give an advantage that is so great that they are not allowed by the supposed experts commissioning these things.
I wouldn't take them because I enjoy reflecting on my JJ and Martial Arts and knowing it is all me. If I was winning competitions on roids I'd wonder whether it was me and my skills or some pills/injections that deserve those medals.
I know 3 people on roids. They are the strongest, most explosive people I know. It could well be that roids attract already strong people as they are involved in that culture, but their strength, recovery and explosiveness always feels unfair to me and I'm not a big fan of rolling with them. I would also add that all three of them seem to have wavering personalities. Again, maybe a coincidence, but I'd not want my personality to change.