When the topic of holocaust denial comes up in the moderation forums, the normal argument is that holocaust denial, while very distasteful, is still allowed in so much as it is honestly argued. However I think the circumstances that surround such an opinion allows it to be considered trolling regardless of the honesty of opinion.
These circumstances include:
1. Complete denial of proven historical fact
2. Politicizing of one of the worst human tragedies from all of human existence
3. The inclusion, more often than not, of claims of some sort of conspiracy by Jewish persons.
I believe that when a reasonable person takes the above into consideration, they will conclude that holocaust denial, whether truthful or not, is an opinion that will only aggrieve other posters. This effect is only increased when we consider that there are posters on here who have a personal or familial connection to the holocaust. There is simply no way to argue or debate with a holocaust denier. Countless threads here and elsewhere on the internet as well as real life discussions have born this out.
Therefore, I believe that it is the best interest of our community for posts that can be defined as holocaust denial to be classified as trolling (or possibly some lesser offense).