Because some twats got on their high horse about it and started some wanky campaign. RBS CEO's bonus? He's doing his job, presumably well enough to meet his objectives, so why not. But, oh no, outragistas on twatter makes it a full on witch hunt until he thinks fcuk it, have it back. All anyone at the BBC seems to want to do is to promote their latest twatter/blog entry (excellent they can get away with only a 150 characters in their "stories") or count up how many wankBook friends they've got in comparison to somebody else.
This is why i hate Milibanana so much. He was in the cabinet when that contract was drawn up (and you can bet it had some scruteny).
If he can't be trusted with a writen contract, black on white, how on earth can he be trusted to deliver against the promises he makes.
That said, in my view Cameron is severely weakened by the Fred afair. Going after an individual with pitchforks is around 200 years out of date, and back then, it was usually initiated by weak, spineless, aristocratic individuals. Politicising the loss of honours is a very very dangerous game.