"...does not one side lose ALL credibility if - for what ever reason - they do not allow the others to have their say?" Not necessarily in all circumstances, in my view. (And I am not sure what "lose ALL credibility" really means when referring to something as non-specific as "a side" made up of a lot of people who have a wide range of opinions and ways of expressing those opinions.)

"Sitting on the fence" sounds very uncomfortable. But it seems to me that to decline to arrive at a fixed judgement about something about which we have relatively limited information is sometimes quite a sensible thing to do.