its a grey area though cos with rnb you can pretty much boycott the whole genre due to crime cos they all work with each other sing produce etc. its like t.i. with gun crime you could boycott for that but then rihanna and justin have both had recent hits with him therefore supported and made money after he was found guilty so you could boycott them for that
It's tricky when it's just one person you are considering boycotting who is connected with a whole load of "innocent" people whose work you like.
On the subject of James Brown, I wouldn't buy any of his music, but his brief appearance in The Blues Brothers doesn't stop me from thinking it's a fantastic film and he's definitely not going to suffer from me refusing to watch it.