So what im meaning is if we all agree that the C-bet is a good aggro play, then how can it not be a good aggressive play with KK and an Ace hits?
To continue the thread hijack for a bit longer, here's the difference:

If you cbet OOP in this spot with 44, you are often getting better hands to fold, i.e. higher PP. If you cbet here with KK, you are getting the same hands to fold, only now they're worse hands that you'd rather take positional stabs at the pot. On an Axx board, there are no better hands that KK is folding out.

Edit: sorry, Zook beat me to it.