MRD applies

While giving evidence at the trial of Stephen Ward, Rice-Davies made the quip for which she is most remembered. When the prosecuting counsel pointed out that Lord Astor denied having an affair or having even met her, she replied, "Well, he would, wouldn't he?" (from Wikipedia).

Hence, "MRD applies" means "he would say that, wouldn't he". Usually used to devalue an opinion by drawing attention to the other-than-impartial situation of the person voicing it.

I think this is a silly idea, myself, but then, I’m a state regulator, so MRD applies.

John Quiggin on badanalysis.com