When I put up my 13500 calorie diet back in 2009, I said (at the time) that I was not exaggerating the numbers, and I wasn't. But I emphasised back then that that way of eating was not done out of want but rather out of need, and only lasted for a short period of about 3 to 4 months. And at 17, (even some girls) have a huge appetite, let alone a 17 year old male weightlifter.
I understand what you're saying about the "hidden" fat we call visceral fat, too much of would certainly spell ill health in the long run. Another point that is not discussed here is the amount/type of drugs this pro bodybuilder is taking and the effects they could be having on his caloric expenditure and assimilation.