Clearly H&M are holding on to a lot of resentment. It's obvious to most people that they're expectations were completely unrealistic. No one leaves their job and keeps the free house, car, travel, security and monetary rewards for said job, yet somehow they think it's unfair that they did not? It's also possible that given the families personal wealth that they could have been financially supported still, but why would they expect support (financially and emotionally) from people who they openly criticise?
The criticism of Kate is pure petty jealousy, although I'm sure Harry feels (quite wrongly) betrayed because Kate wasn't besties with Meghan (when they have very little in common). Meghan I feel has always been competitive with other women and finally met her match in Kate, because Kate won't be bullied manipulated or charmed into doing Meghan's bidding and that's not something she's come across too often, I suspect.
Spoilt, self-important, conceited couple who seriously think that everything should revolve around them and only them.
As for Omid, he's not done himself any favours with this book. It's not journalism, it doesn't even pretend to be. His credibility as a writer is pretty much non existent after this, if he ever had any to begin with that is.