I think it depends how you feel personally. I find actually hearing R Kelly and Chris Brown's voices difficult knowing their pasts and the various allegations they've faced (and continue to face), but production and co-writes aren't as conflicting for me. I deleted the R Kelly duet from ARTPOP and replaced it with the (superior) Christina version, and as of yesterday, the solo version because I didn't know this existed until then. But, as an example, I don't feel the same sort of conflict when I listen to Britney's "Outragerous" which was co-written by R Kelly because he doesn't feature vocally. Another time I can remember feeling put off by something like this is Rolf Harris's feature on Kate Bush's "Aerial" album after he was convicted. I'm so glad the re-release replaced him. But, I don't feel the same sense of dread when I listen to Kate's song "The Dreaming" which has Rolf playing the didgeridoo.