That is the biggest problem, WHO draws the line or WHERE does the line get drawn, only way is zero tolerance, that has been tried before but as in reality it never will work on an open forum.
If the forum is a true cross membership of pigeon fanciers then you will get a true cross posting of views like you would in any forum, pub, club, workplace or gathering, the trouble with the internet is it is not a natural tool of interaction. As soon as you meet someone in person you get an idea of how they will react, you will never get that on a computer screen.
The difference is some has a delete button and a lot of things that in person would be dealt with or shelved,
Me personally love the banter, I can look someone in the eye and tell them the truth as I see it also look them straight in the eye and tell them they're a lying git as I see it
I know that there are members on here that cannot deal with banter and would like to see it banned and members that cannot deal with the truth and would to or love having control of the delete button :-/