Gulliver - when a friend is accused of something you are absolutely sure they have not done, the instinct is vigorously to defend their reputation, especially if they are not around to do so for themselves.
If that friend is a respected public figure, the sense of outrage at perceived smears on their character leads to ever more intense defence from friends and admirers.
From indirect personal experience, watching my wife fight for her professional reputation when investigating physical abuse claims against a much loved teacher in her school, I know just how intense such defence can be, with howls of disbelief that anyone could even think such a thing, and how 'evil' anyone must be to believe such accusations.
I also know from sight of evidence, that such claims can be true, however seemingly unbelievable they may appear, and friends would wish them to be.
When people say Friend X 'would never ... ', sadly they are deluding themselves. Anyone could, given the circumstances, no-one is ever immune simply because they are perceived as 'not the type'.