The emperor-that-would-be has no clothes
TAKE a moment and look at this video. Once you're done laughing, watch it again, and think about what it reveals. The fervid desperation to sanctify McCain's military service, to protect it from all future assault, make it clear for all to see that other than his military record (which is far from exemplary), McCain has absolutely nothing to stand on.
This is the reason for all the outrage, the head-shaking and the hand-wringing. They know that the illusion has to be preserved at all costs. No one must be allowed to see the truth behind the lie, which is that the emperor-that-would-be has no clothes.