So what if his apologies are not in the public eye or convincing. As long as he did it to Rhianna thats all that matters.
Fact she took him back proves she did and they have both moved on, everyone else needs to do the same.
Actually people are allowed to have their own opinion about CB regardless of what Rihanna may think of him. He will most likely be forever at the end of punching jokes, people will dislike him, and if he can't live wit it, well, that is actually his problem.
As for CB "doing time" he has done none, and his community service attendance seems to be a bit dodgy as well according to recent reports. All he got from beating up Rihanna, was banished from the Grammy's for 2 years, and a bit of a public backlash. That's much less than many others gf beaters get.