Because they are so far always either not true or things that every single other member of the royal family does routinely to little or no comment
If you're so convinced of this...why ask yet again?
But ok. Lets just deal with the latest faux pas. Do you think this very public and somewhat intimate letter in which he appeals rather unambiguously to public sentiment by comparing his wife to his mother, drawing upon the latent sorrow of her tragic passing, and then ends with a dash of the melodramatic 'we need your good wishes' - or some such other - is something 'every' royal has done? Do you think it prudent? Do think it quite becoming of Royalty? Or is it perhaps something a high profile celebrity would more likely be expected to do? Do you think it likely to diffuse the situation or add heat to it? Do you think he ought to have sought out and received better advice before writing it, or do you think he was justified regardless? Which other RF members have issued such a personal, open and direct letter to the press? Do you think that if you want privacy it might possibly be mindful to not be quite so open? What about the timing? Is it wise to do this now? Is there in reality a direct comparison between M&D?
These are pertinent questions. We are talking about them because they have done something. We are not talking about Anne or E&S or even Fergie bless her, because for the most part they are quiet.
Because a few months later when a thread of this sort inevitably turns up again, amnesia will have once again set in and people will again be asked but what do they do wrong? Or What do they do that other royals don't? Love them or loathe them, the thread is about their actions which are obviously open to interpretation dissemination and yes judgement or praise.