It, of course, is a part of our libertarian philosohy to exercise our private property rights. Those rights, however, do not trump all other rights. This is, in essence, like a place of business. Any good Libertarian business, and in general, any good Libertarian, would like to protect as many rights of others around them as possible at all times. This includes free speech. There are limits as to what is acceptable on the BBS and those are very public.
Our rules are there to maximize freedom, and force is only used when it becomes quite apparent that the troll is using aggression to affect or deprive someone else of their freedoms.
This is why there will always be some problems around.... Because freedom isn't free, nor is it simple, or calm. Freedom is tempestuous, and full of problems and challenges to be overcome.