Camilla was the person that the then Prince Charles should have been allowed to marry when he first wanted to, back in the early seventies.
The obstacles to that were his rather foolish family who thought they knew better and eventually pushed him and Diana into that disastrous marriage which was a nightmare, not a fairytale. Some of Diana's family were equally obnoxious.
I think Camilla can absolutely be forgiven. It's a shame it took the senior royals so many decades to see sense but thankfully Charles stuck to his guns this time and declared that she was "non-negotiable." As a young man in the early seventies he perhaps had much less confidence to stand up to his parents, who were leaders of an institution like the Royal Family.
Meghan - I don't hate her. I'm not sure she fully understood just what she was marrying into though and perhaps thought that experience of the press and paparazzi in Hollywood would prepare her. She didn't see that the Royals are a whole new level of that shit. I do also think that the Royals themselves could have done much more to support her against the utter racism in the media but they chose not to, taking the "never complain, never explain" mantra, which often does serve them quite well, much too far. In doing that they came across as aloof and unsupportive.
I would agree that plenty of what the Sussexes have done was damaging and unwise (Oprah interview etc.) but there was fault on both sides. I really don't think very much effort was made to support two clearly unhappy people and try to find a role for them that was a better fit.
Half in, half out has been done before. The Duchess of Kent for example, who was unhappy in the full glare of royal life.