Oh I think they care. I think you're underestimating the extremes to which delusions of a parasocial relationship with a celebrity can go. And the extent to which the sunk cost fallacy will push individuals into insisting ever more forcefully that they are on the right side of history, employing ever more vicious rhetoric and tactics to make their point.
I also think we shouldn't underestimate the strength of the 'legitimate' (ie traditional) PR campaign that Harry is pursuing in this debacle. Using Rayner as his mouthpiece was a disaster, but employing the Tory peer and other unnamed insiders to smear SC as 'dictatorial' and wasteful in spending money on consultants, has undoubtedly gained some traction. It's one of the oldest dirty tricks in the PR book, involving the ad verecundiam fallacy: get someone authoritative sounding to smear your opponent as a person, so that the opponent's arguments won't be taken seriously. And put enough distance between that authority figure and yourself to appear to keep your hands clean.
These are all really nasty, old PR tactics. The kind of thing that Alastair Osborne (a truly sinister and amoral individual) used to employ, and it's been everywhere since last Friday. Not terribly well hidden either, which is what does surprise me - the extent to which Harry is blatantly willing to attack HIS OWN CHARITY AND THE BENEFICIARIES in order to win a PR war. You could make a decent moral case that what Harry's doing is actually several degrees worse than what he accused the Palace of doing in Spare.
If not protecting Meghan from 'racist media'* is morally wrong, then how much worse is launching media briefings that could sink a charity that was set up to help vulnerable people?
It really is one of the most destructive slash n burn strategies I've seen in quite a while. I would almost describe it as warped.
*The British media was NEVER ONCE racist against Meghan and I will die on that hill waving my receipts.