I dont have a forum but I dont think swearing is a nice thing that should be allowed anywhere. Swearing hurts someones feelings and forums are ment to be a safe space for people.
I don't like swearing on any forum I own. I especially can't have it on my Christian forum because it is against Christian ethics. And I generally don't like swearing in general because it is against Christian ethics, and it just seems trashy. I mean, I remember teachers who cussed in middle school, high school, and college. These people really lower the respect of the profession and some of them are doing it to show their rear end, honestly.
And what would I do about swearing on my websites? I don't really know. I haven't encountered it yet.