Charles and Camilla behaved badly to their former spouses and were poor examples to their children. But who among us can cast the first stone? This isn't really about them anyway. If it were, we could all throw stones, or pies, and enjoy ourselves.
It is about us and that is why so many of us loathe their image. They remind us of our own ugliness. It is why so many magazines and television shows carry news about "celebrities," people who are mostly known for being known and who do not have a record of achieving much worthy of more than passing fancy. Idolizing their false images helps us deal with self-consciousness about our own.
Why do we celebrate celebrities who behave no differently from Charles and Camilla? It is because celebrities are beautiful. Adultery, divorce, cohabitation - all of it is forgivable, even enviable in them, so long as their beauty and glamour elevate our sense of self-worth. If a plain or homely person behaves "badly" (whatever "bad" is these days), then it's off with their ugly heads.
The wedding of Charles and Camilla is a play within a play. The real storyline is being acted out by us, not them. They are but a mirror. When we see ugliness, instead of the beauty we had thought was there, we condemn the mirror.
Mirror, mirror on the wall, who is the ugliest one of all? And the mirror replies, "You are, baby. You are."