I have been on a number of forums but the only one that seems unusually rude where any comment will bring a few negative or unfriendly comments is the largest, DPR. It is depressing to be around the negative attitudes.
I am a moderator for a large Nikon community with 285,000 member that is very polite and supportive, sometimes too polite. Overall, ALL photography forums are pretty tame compared to anything political, music, cars, sports, celebrity/media where the level of discourse is crazy in personal attacks for minor differences in views.
Photographic forums are more civil than photographic equipment forums. Gear heads mostly argue about equipment and not much discussion about photograph as an art. A lot of gear envy or hostility out there. I think the conduct on forums reflects the nature of the societies the posters are immersed in.
I find overall the US has become more intolerant and argumentative and notice a distinct difference every time I return back home. I don't open my mouth much on visits back because there is always some word or comment that that will cause a emotional reaction. It was not like that 30 years ago. I retreat back my my adopted home city where no one seems to take offense at anything, and almost any encounter is polite and friendly. I think the general level of discourse becoming more aggressive is one reason I don't see many people go out at night when I am back home.
This is a good community, I was welcomed warmly when I joined a month or so ago.
My only nit to pick at is the structure, it has a LOT of low posting forums by model number when activity would increase if they were concentrated into a smaller number of forums. For example, having separate forums for each similar model in the same series, means a question or comment that might be of interest to anyone in the model series range, likely is not seen unless they have the exact model for the forum it was posted in. Almost every question about a camera, say, D7200, also applies to all D7xxx cameras, but will likely only be seen by those with D7200. The appearance of activity breeds more activity, something forum admins found years ago, and activity is what keeps a forum viable. Same with retail stores, restaurant, or clubs, we tend to gravitate towards activity and the lack of it is the number one reason for people to enter then leave a bar, restaurant or furniture store etc. The does need more activity.