Actually I think Harry is just being vindictive because he is angry and resentful. Remember he never ever intended to stop being a working royal.
They left for Canada and wrote that daft letter about how they were going to earn their own money and collaborate with the queen and be this new hybrid of working royals shaping the monarchy, splitting their time between here and the us….,..then they got slapped down by the royal family, most likely Charles, and lost their titles, their met office protections, all their patronage’s and were told you’re either in or out, you can’t monetise your position like that.
So now they are out and he’s angry and resentful. It was never ever what he intended. The fact what they intended was never ever going to fly is irrelevant, they thought it would, they didn’t get what they wanted, and he’s angry bitter and resentful about it, so giving his family a thorough kicking becayse he thinks that’s why they did to him.