There must genuinely be something wrong with her. I've heard people say narcissitic personality disorder, sociopath, some kind of neurodiversity - could be a combination of more than one thing. It is interesting, there definitely must be something going on with her as its not like she's thick, she's average/normal intelligence. She doesn't seem normal to me, and I wouldn't say that lightly about anyone.
She's fascinating (horribly, I admit) partly because of her jaw-dropping, textbook narcissism - it's rare to see it exemplified so blatantly in real life.
I suspect her childhood experience of Hollywood film-sets has skewed her attitudes and personality considerably, It's a shallow world where superficial appearance and behaviour is what you are judged on. She will have seen gushing, insincere behaviour from film-folk - all actors will tell you that they need to establish close, even intimate, relationships with their colleagues almost instantly, and this is how it works - the old 'Darling!' culture, though that's more British. Then, when the filming is done, most of them go their separate ways and these 'friendships' evaporate.
She'll also have seen at close hand the importance of hierarchy in terms of star-rating - and the inevitable jealousies and jockeying for status - maybe even learned that the way for women to climb the greasy pole is the old, traditional one of using their sexuality.
Clearly Meghan's family are a strange lot, and that's putting it mildly, and she hasn't fallen far from the tree. Where WAS Doria, during those years? So bizarre that's been successfully suppressed - was it the RF/secret service who have helped to keep this quiet? I feel sorry for M's father - her treatment of him (on the face of it) seems appalling.