"Any assumption that Harry's children would automatically be princes or princesses, even once Charles became king would have just that, an assumption..."

At the time Harry and Meghan were married, that was the protocol established many decades ago, before this queen was queen. A son of the couple would be made a prince once Charles was in the throne. There was no hint that that protocol would be changed until Meghan was pregnant. I think they have the right to feel aggrieved. And suspicious as to the racial context of any such change....