The forum is run on a phpBB platform. Banning and limiting access is easy enough to do through the administration control panel. I'm sure that if the mods saw fit then the trolls would be banned. As it is this is a very active forum and for an administrator to be online 24/7 and constantly working to keep the forum clean is a massive task for anyone.

I used to run a forum for 300 active members and that was hard enough. This community spans a helluva lot more than 300 members.

I personally feel for the admins that have to moderate this forum.

The answer is simple.

DON'T FEED THE TROLLS!