Can't speak for others, but I downvoted because the OP's explanation is absurd. Yes, Trump's absolutely a liar, but the absurdity lies in the claim that the media's "outmoded norms" (i.e., honesty, objectivity, neutrality, etc) inhibited it from calling out Trump's lies is ridiculous. Honesty doesn't inhibit an institution from pointing out one side's lies, on the contrary, honesty demands it. However, honesty also demands pointing out the other side's lies, and therein lies the rub.