I suspect the root problem is not the forums per se but the members attitudes. In my experience no matter what you discuss in real life or in a forum cannot always be agreed upon even in the face of overwhelming evidence. The discussion will start out amiable and each side of the debate will use its knowledge and evidence against the other until one side is clearly either stronger or simply more resourceful than the other. One side then being backed into a corner will either concede and as some put "see the light" (though what they do privately.....) OR simply don the "la la la I'm not listening headset" but still continue to post. The circular argument that is often cited is ofter due to this behaviour. In the face of evidence and outside resources, it is amazing how much illogical argument can have weight purely because others in the discussion support the original view.
As a society we hold a lot of stake in how much our words and actions mean to those around us even to strangers on the Internet. To lose face for many in a forum seems almost shameful....
Personally if you can beat me down I am willing to accept it, I believe that is what makes me a stronger and better human being, the ability to learn from my mistakes. That way I can use your own argument against you next time
