Racists, Bigots, and Xenophobes. How should we best deal with them on YA?

I accept that they vary in degree - from the uninformed to the excessively tribalistic. There are many - some overtly so, and some who covertly attempt to disguise their own attitudes by asking questions they know will provoke biggoted answers from others. When I first joined YA, I would have said that they should be reported and banned; but now I'm less certain that such censorship is the right way. Perhaps we should just let them reveal themselves - then challenge their beliefs and attitudes through rational and informed arguement. It's hard to say how accurately YA represents a cross-section of attitudes in the British population. If it does, then by allowing it to expose itself at least we get to see the size of the problem. My question was inspired by the recent controvertial announcement that BNP Leader Nick Griffin and Holocaust Denier David Irving have been invited to an Oxford Union debate.