Running KK into AA is a classic cooler, and it always sucks, weather it happen in the first hand of after 4 hours of play. But as others have said, the hand history is incomplete, and the line taken at least questionable, especially the decision to lead out on the flop after having just called preflop.
Everybody will lose a big pot, when they run KK into AA, but there is a big difference between losing 40% of our chips and all our chips. And maybe Hero actually lost to much, especially if the event started with deep stacks like 200BB. KK is not the nuts postflop, unless we flop top set on a dry board, which was apparently not the case here.