I think that the plot was written to be complex in an incoherent way, and not in a deep way. Japanese directors seem to have this issue where they think they're creating a deep work of art, if no one understands it. Now you might say that it's easy to understand, and maybe I missed something, but I find that the people who generally argue against this just fill in the ambiguity and vagueness with their own story. This happens in music, people take a generic lyric and add their own depth to it.