Pulling head down is an intentional move to take steam out of opponent. It's just very tiring. I'm all for enforcing the rules properly, even after the match, based on replays. I don't care much if something like this happens a few times in a fight but as I said - watch it again and imagine Ali can't do it at all. How long do you think he'd last? I can't give him credit for that, same with Maradonna's handball etc.