There's usually no point debating with racists, homophobes, sexists (I've seen plenty of sexism on this board too.) At some point I flagged a conversation that seemed blatantly sexist to me, and the person got a warning, but didn't see their views as sexist at all and started to cry censorship. Whatever. I tried to point out why their comments were offensive, but they couldn't see or were unwilling to understand my POV and were far more upset about being censored, as though they were the victim of the situation. No acknowledgment or willingness to see another point of view.
Overall I find the mods reasonably willing to shut down offensive commenters or threads. In the thread linked to above, it seemed as though the OP has shut down the BMI conversation well enough. What else can you do other than call them out on it? Either in a comment or by flagging the mods? IRL I do not engage in debates with bigoted people, because in my experience they have chosen this viewpoint and do not want to change it. The conversation goes nowhere. All I can do is say "that's sexist / racist" and walk away from them before they start in with the usual anti-liberal rhetoric (see post above.)
There's a difference between tolerating bigoted behaviour and disengaging with it. If anyone has a better solution, I would love to hear. It would solve a lot of problems in the world today if people could have real, open minded, thoughtful and engaging conversations about these issues. But most people are not interested in engaging beyond the usual automatic responses to criticism (claiming censorship, using anti-liberal rhetoric, denying and deflecting, etc).
In the case of the BMI thread, what else can be said? I 100% agree with OPs comment there but I see the thread and think it's already been shut down and I have nothing to add.