Bradley has made himself look like an idiot, without any help from the Knighthood!
I thought he was something of an idiot before, so I agree with you there, however, the Knighthood probably draws more attention to his idiocy, and gives people something extra to moan about.
Some people have very certain ideas of what is acceptable behaviour for a "knight of the realm", which are mainly ridiculous, because the sporting ones at least tend to be earned because you are really, really good at something, not as a reward for sucking up to the right people, the I'm sure the Knights in King Arthur's day weren't bothered by etiquette.
However, it would be an extra burden that Andy doesn't need while he's in the full glare of competitive tennis. Personally, I think they only gave one to Wiggins before retirement, because they'd given one to Hoy, because they thought he was about to retire, and he's also a nice public school boy who didn't ruffle feathers.