No matter how well-intentioned, that statement is the first step in a long path leading to censorship and political correctness, even if for appearances' sake. Criticize them for what they said (after all, it will be on the record), move off to another thread, whatever. But don't attempt to censor their right to say what they want, even if by reasoning with them. If what they say gets out of hand, the moderator will blast it.
Too late, we've already started down that slippery slope.
Don't get me wrong. I am NOT going to censor anyone. Not my job, not my right, and not my responsibility.
I am one of the most ANTI-PC people you will ever meet, I believe in Freedom of Speech.
But I also believe that with Freedom comes Responsibility.
I am trying to get people to filter themselves. Because even if a moderator gets is appropriately, it may already be out there in the world. And no matter what anyone tells you, reputation DOES count.