I have watched this movie countless times over the years and it never fails to impress. Unlike lwjoslin, I don't purport myself as a historian. But then, the story of Camelot, King Arthur, Guinevere, and the rest are NOT historical figures in any true sense. They are all fictional characters in a fictional setting.
So why write such a derisive review? To me, it seems clear that the reviewer is incapable of simply viewing this as pure escapist fare. He (or she, but I doubt it) most highly thinks very highly of himself. I hope that people were not put off by his diatribe. He, and those who may be influenced by his critique, need to remember that the entire story is fiction. It is not based, in any way, on historical fact. To make the comments he did, he must have forgotten that simple idea. It is fiction, and the story has simply been embellished in a new way.
For me, this was a wonderful story of a wonderful time. It is a story which has been told many times on film within the past century, and has almost always been presented as a tragic event in an otherwise idyllic time. Why does he insist on tarnishing this telling by citing irrelevant facts? Do not be influenced by his trash. This is simply a wonderful, new twist on an old story, and it's very well done.
Enjoy!