Haven't experienced that. Zeev is an ardent proponent of free speech. My guess though is if there were a thread where such was happening, I'd move on to another thread. There's plenty of people who wouldn't like my political views and if I went on their thread and posted them, they'd probably boot me. I don't see that as Matt's problem.
I generally am not willing to waste my time on flame wars that have no point.
Posts which were copies from hate groups were deleted, not because I just disagree with them and they are nothing but ear mongerers, but these were completely tasteless. One poster was banned since he insisted on not providing a fair apology to an extreme gross offense, he was given ample opportunity and a vote. For a year or so of activity, I think that is not a bad record.