I have a relative (and their partner) that at times reminds me of HAM.
Thing is, it isn't enough for them to live their best life and let everyone else live theirs: Everyone else should be jealous of their life and realise it's far superior - and say it frequently.
One example was when we bought our first house, at a similar time to them. We asked them what it was like, them never having seen our house, and the first words out of their mouth were "well it's bigger than yours". On paper it was exactly the same number of rooms, and floor area was so close as to be uncommentable. Fine they liked theirs better: we liked ours. Who cares?
If we ever had something they liked, they'd either go and buy a bigger/more expensive one or rubbish/break ours. It was a one sided competition, as we were perfectly content - actually we found it quite amusing to see how long it took to get their version.
When I realised the issue: it wasn't that they had to be happy with what they did; they felt we should have been brimming with envy at what they had/did, so the fact we were perfectly content with what we did/had was driving them to distraction.
Similarly, they present an image that the whole world is waiting to fall down at their feet in awe and wonder at their magnificence. They've occasionally been totally floored when we've been there and the room hasn't risen to their feet to applaud, despite on paper there being nothing special about them and been in a foul mood afterwards. When I at one point asked why they would expect it, bearing in mind that there were lots of people in the same position as them they stammered out "but it's me!"
They like to give the impression that they are loved by so many, people can't get enough of them, and people think they are just amazing at everything from their job through to personal life. I work in a similar field, and not infrequently come across references to them. A few people, generally those who haven't had too much contact, are reasonably positive. But those who have worked closer I hear they're bullies, especially to anyone who may challenge them, arrogant and set themselves up as experts by speaking confidently at a subject they know nothing about.
I actually feel quite sorry for them because, despite all their posturing at being the most popular couple in Britain, I don't think they actually have any friends they could rely on in an emergency - or even to babysit (I know that one for a fact!) for an evening.
If they're out, they will act as "the life and soul of the party" by being loud and silly, and gather people round them. But that doesn't translate into real friends.
It's not enough for them to do their best and enjoy something; everyone else needs to think that they are the best and envy them.
I see something very similar here. For HAM it's not enough to quietly do what they want and make friends and enjoy the side effects of being RF. They have to be seen as doing it better than everyone else, to be more Royal than the RF, have more important friends than the RF, and get better media than the RF. When they don't, they don't understand why because they know they are better than everyone else and so they have a strop because people aren't acknowledging it.
So the attacks on W&K are simply because they won't acknowledge that HAM is better than they are. If W&K would only do that, then they wouldn't have to try and knock them down to prove it!