Sorry - did Harry himself complain about the coronation happening on Archie's birthday? If it's just conjecture as I expect, then I don't think they're that upset about one day. But it isn't one day. The anniversary of Charles' coronation will always be on Archie's birthday going forward. This isn't a one-time deal, necessarily. But in the UK, Archie's birthday will always be second-tier in his Dad's family. That kinda sucks.
Otherwise... Harry's stupidity in the book hasn't really changed my opinion on the whole shebang. Harry was always the wild card, in trouble the most, careless and thoughtless as a young adult. I've said before and I maintain: he was never going to be happy within the confines of the Royal Family. He's way too much like his mother, and he was never going to be able happy just being rich and trotted out for events. Good for him for getting out.
Again, I understand that a lot of what he's saying and doing is ridiculous to many. I think most people who have issues with Harry come from stable families, or at least had one parent/a few family members who made them feel valued, important, safe, and seen. For those of us who didn't have that growing up, a lot of Harry's actions are... somewhat relatable, though that's certainly a strong word.
It continually blows my mind his detractors have so little empathy or understanding for him-- or more correctly, seem to buy into the stupid circus that is the british monarchy without question. I don't even mean claims the "Firm" leaks stories and had it out for H&M, I mean their very existence and choices made to serve the firm in the first place. All in the name of tradition and a serious abuse of the word "duty." What duty does this family actually perform? Walking around waving? Showing up to charity events and doing very little but smile and nod earnestly for cameras? It's rare they actually DO anything but they're given so much leeway because that's just how it is. I find that pretty ignorant and ridiculous. If Harry has to make himself look worse in order to take that whole institution down a peg or five, I am HERE FOR IT.