Maybe the coaches like seeing them that way too. haha But I agree with your point. I would think that with as much grabbing and groping that goes on on the mat, I would want to at least wear underwear or even a jockstrap to keep things tighter and better protected. And that's not even addressing issues of modesty. It seems to me a bit more protection would be a good idea if one plans on having children later in life.
But still... I have to admire the show when hot, hunky wrestlers want to flaunt what they've got and leave very little to the imagination. haha