Like Donnie Darko
Shhh, don't try to explain it. Enjoy it or don't.
Like life and all of Earth, sometimes things happen for reasons beyond logic. If you want a linear story with a nice neat beginning, middle, and end, everything all wrapped up in a nice little package, this is not the film for you.
I'm only defending this in the same way I would a painting or an album for not telling a coherent story, it's a piece of art in the same way as those. In my opinion anyway, I've watched many similar films to this and find them much easier to enjoy with that outlook.
I can't pretend to know the thoughts or intentions of the writers and director, like so many other "reviewers" seem to be able to. God damn telepaths all over IMDB man.