I think it's because people here try to get away from typical imageboard culture. A lot of people here just want to have discussion and not spend all day trying to flame. Also it helps that there's no images to distract from actual post content.
I like it when a place doesn't have a hostile atmosphere, so long as it's not enforced. For instance, a few small imageboards I've been on have tried to enforce comfiness and non-hostility, and it is forced and not genuine. That really kills the spirit of these types of sites.
For this place, I honestly just think this place is a break for them from typical IB culture.
That's how I see it anyways.