He's not doing anything wrong, really.
I strongly feel we shouldn't do anything about it. It's just free speech - and the point of any kind of principle of free speech is that it is *free*. There is nothing inherently different about his reasoning than yours. You might not agree with it, but that's not relevant in any way to the concepts I'm trying to get at.
If you put your own reasoning in a different class than his, you damage both his reasoning and yours, actually - because then you will take away from looking at both his reasoning and your own as what they truly are, and no more, which will allow them to be more truly seen. And, coincidentally, if either his or your reasoning is not borne out in reality, censoring him will prevent actual flaws borne out of actual reality from being seen in either one of your logics much more than not doing so.
A small pocket of cyberspace free to the truly open expression of ideas is a lot more advantageous, to me at least, than one where the views are constrained to what we all collectively agree is "okay".
This is a tiny internet forum, in a small corner of the internet that no one else knows about, or probably would even take the time to really care about if they did. Harsh as that may sound, it also means we are, at present, freer here to express different kinds of opinions than maybe anywhere else on the 'net, or even anywhere else in the world, probably. Speech here should be about as free as it gets - the only impediment to free speech is our own decisions to act on censorship based on our existing biases, which is not a very separable problem from speech in general in any system that allows for said type of censorship.
The lack of censorship here lifts me up on a regular basis, and I would like to strongly state that I cast my vote to see it stay that way (assuming that this is any sort of democratic process).