A quick perusal of Wikipedia shows that four of his six albums, and one of his three tours came about AFTER his girlfriend was publicly photographed with worse injuries than any visible, ever, on Janay Rice. Since the year of that event (2009), he has been nominated for 5 American Music Awards and won one. He has received 9 BET awards and been nominated for 9 more. Prior to the domestic abuse he was nominated for 2 BET Hip Hop Awards, and AFTER the pictures of his girlfriend's battered face had time to circulate, he won 3 of those same awards. He has won 1 Billboard Music Award and been nominated for 6 others, along with 3 Latin Music Awards & R&B/Hip-hop Awards, each, from Billboard.

As for the Grammys, which apparently take politics and current events into account, from the fuss everyone made about the Dixie Chicks being vindicated when they won after the backlash against their political comments, he has been nominated 7 times since his domestic violence incident, including his only Grammy win. If the Dixie Chick's Grammy vindicates their unpopular behavior, then does Brown's 2012 Grammy vindicate his battering of his girlfriend?

He also one two MTV VMAs since the assault, with three more nominations.
He has been nominated for 2 NAACP image awards, won 2 People's Choice Awards the year of the assault, and has been nominated twice since then.

And that's on top of a bunch of other obscure things I never heard of. In skimming down the list, the only mention of his domestic violence incident was when Nickelodeon pulled his name from consideration for their awards, and he has not been nominated since.

For Brown to be treated like Ray Rice, he'd have been locked out of all those awards, and a storm of public outrage would have been calling for his albums to be withheld from release, and he'd have been banned from setting foot in any significant recording studio. Even if he can't be stopped from playing and recording music, the big distributors and awards organizations should have faced same cries for their heads to be fired for not moving fast enough to blacklist him.