I've given some thought to my rather open comments policy, but I really do believe in keeping an open intellectual atmosphere. Further, I am convinced that people making up their minds what to believe are influenced as much by the kind of person a belief makes you as they are the with the strengths and weaknesses of the arguments presented, which may be not be easy to assess. So if you are committed to an ideology that is deeply at variance with my own, and you want to be a jerk about presenting your position, my reaction is "Go ahead. Make my day. Take all the rope you like and hang yourself." The fact that I might not delete a comment does not mean that I approve of it or the tone in which it was presented. I do not feel that I am obliged to comment on everyone's comments, so if I don't respond please don't be so egotistical as to suppose that your comment is so brilliant that I am "ducking" you. If you start saying things like that I may indeed show you the door. I may fail to respond because I don't have time, or because I feel I need to think for awhile, or sometimes because I really don't think it deserves an answer.
I think people have an obligation to their own beliefs to defend them in a ladylike of gentlemanly fashion. This, of course, does not exclude passionate advocacy of what you believe.