How much is a lifetime of 24x7 private protection for you, your wife and your children, so potentially 3 security details in three locations, plus another for the family home. What is his income? He didn't ask to be born 'royal', he didn't ask to be pushed into the public spotlight at and cruelly made to play out his grief in front of the world. I've had the choice on how much to involve my 7 and 9 year old children (at the time) at their mums funeral, the idea of parading them like that is shocking. So I feel empathy for the guy, I understand why he's seemingly angry at the whole life. But he never asked for it. He's seemingly rejected this life he didn't ask for, so why should he financially suffer because of it?
He got some income inherited from his Mum, but IIRC it wasn't the kind of money for a lifetime security detail. He has to find an income stream, if he's monitising through seemingly attacking the very institution that have harmed his happiness and mental health then that is his choice. The royal system cannot be allowed to exist free from critiscism, purely because some people slavishly adore it.