Because he shot Obi Wan in the back.
If Cody shot up all the padawan I'd have ordered him by now, that would have been memorable.
Come to think of it, that's probably a better idea than having Anakin do that, whom we should have seen taking down other Jedi rather than a bunch of hapless kids.
Because he looks cool.
That makes sense.
If you can only have one clone, it should be Cody.
Cody... King of the Clones!
Canada Clone (who may have gone missing) would disagree. An army or nothing!