I think this too. I think he's a very private dad - generally in public he has his "king" face on which is the quintessential stiff upper lip.
Harry wants us all to know how he was never taught to ride a bike, never hugged etc. Except that private photos from when Harry was young have since been found which show - shock, horror - that Harry was lying. Again. Photos of him riding bikes with his dad, having a piggy back, and general, loving photos with his dad hugging him. It's all such bollocks from Montecito.
I think Diana was pretty good at manipulating the press before social media was a thing. I liked Diana; she did loads of really good work and made such a difference...but I'm aware she was very skilled at persuading the press that Charles was the bad guy.
And I think this perception has just continued, probably unfairly. When you see Charles with his grandchildren, and even with William and Catherine, he seems to have warm and loving relationships.