People have to individually decide where to draw the line when it comes to judging a work of art by the personality of its creator. For me, I think the whole practice has gone too far down the path. I want to remain relatively ignorant of people's personal politics and dumb opinions. I don't want to purity test every piece of media I might potentially enjoy. I just want to enjoy it.
WRT the Harry Potter series, I was always a half-assed fan, enjoyed several book and then dropped them at a certain point for no good reason but my attention span wandered. I'm currently enjoying reading some fics starring Draco being moody and suffering in various ways, and enjoying that. JKR is an ass, but that's kind of neither here nor there for me. Do we burn all our Weinstein Company DVDs? *shrug*
Sometimes bad people make good art. We'd all be blissfully ignorant of this, and probably coexisting a little more peacefully, if it weren't for the internet which ensures we all have virtually no privacy and our worst personality traits are out there for the world to see.