That video is probably the best support for the theory.
In isolation, it is one heck of a convincing argument, a great interpretation. It is helped by its brilliant editing too (though the subject matter does highlight how juvenile, melodramatic and occasionally embarrassing writing in games can be).
It is just an interpretation though, as it intentionally doesn't explain the many problems with the machinery of the ending (ie lack of meaningful choice and consequences), or the Adam and Eve allegory and so forth.
As it doesn't exist in a vacuum I don't think it stands up to any sort of rigorous examination, as seen in this thread and elsewhere - and I don't want to open that can of worms again!
Nonetheless, I really enjoyed it.