I think the best thing to do is to just let them talk **** about other artists. If people don't pay attention to them, then they'll know that no one gives a crap about what they have to say. Unfortunately, people don't always ignore the haters...
I think what needs to be realized is that those haters have no lives. They are going on the internet to badmouth other people. I mean, that's seriously really lame. The internet is the most cowardly place to start trouble.
And also, why does it matter? Why do you have to defend yourself? You're never going to meet these haters in your life, so why bother yourself with their stupidity? As long as you enjoy your favorite artists' music, then you shouldn't let what other people say get in your way. They don't matter. You can't help what they're gonna say, so just live and let live