In behavior where there is no competition, i.e, what you eat (or don't eat), that is fine. But, when you put multiple players into a situation where advantages slant the potential results of the competition, it's no longer just a matter of personal opinion or preference. There are basic rules to a game. In a race, the first person to the finish line wins. In a race, you must all complete the same challenge, i.e, run a 3.1 mile distance. Then, there are more complex rules. In a race, you may not manipulate your biochemistry to allow superior physical capabilities. The first, simpler rules are easy to adhere to. You watch the finish line to see who comes across first. You make sure everyone runs the same course. But, for more complex rules, you have to put some standards. Competition has agreed upon rules. Whether moral or not, they are the conditions by which the game is played. If it's "all up to the individual" as to what is okay and what isn't whose set of rules do we play by? This is a common issue in game theory. Unless there is an authority determining the final conditions and results of the game, there is no way to actually play a competitive game. You dismiss morality and say to each his own. That's fine when each sticks to his own. But, when it becomes a matter of competition, people are not sticking to their own any more and it's no longer just about what you or I or any one individual thinks.