I think the major difference is that past performance element.
It might look identical to you, but to us you have an unending history of not listening, accepting you are wrong or even accepting alternative views as plausible.
Whereas take Dunc, he has a history of accepting people disagreeing with him (other than in relation to his opinion on Asian women). I am not sure he has always been gracious in doing so (Lewis Grabban ahem), but he is at least accepting of other views all the time and has changed his view in response to healthy debates.
So yes, it is double standards with you I'm afraid. It means that you do need to go the extra mile to show what is your opinion (and you will accept challenges to it) and what is fact. At the moment, there's still no sign you will - you are still yet to admit being wrong on things (and will recall that on one occasion you admitted being wrong, before promptly retracting that). So that's your past performance.