Go with your instinct, it has always served you well. This is just my opinion though, but a person who writes hateful racist remarks in a public forum feels that way. It's unacceptable no matter where it was said.
But if I do that, where do I draw the line? Would it really be acceptable for me to ban everyone from this site who says anything derogatory and hurtful about anyone here on any other place on the entire web? That sure would be a lot of territory to cover... It may actually be best for people concerned about such things to just stay away from those places where such people frequent. There is a lot to be said for the "out of sight, out of mind" philosophy. I am actually quite comfortable knowing that I have ejected certain persons from my "world" here and I don't have to read a single word they will write ever again unless I choose to do so.

I might as well just stay in bed under the covers because people like John, Joe and their ilk are EVERYWHERE and there's no avoiding them. Sometimes you don't even know who's what until you open a message like the ones I received.