Are you asking why it works this way or are you asking why they don'tsimplify it?
This isn't something I can explain better than I have I'm afraid because I'm going off Nate's responses to this card and the short version of a flowchart. I expect the full version to either be laid out in a fashion that makes this obvious, or errata on the card (Nate did say he was concerned about how confusing it could be and how it may restrict future design space).
It would be simpler for it to be considered a window unto itself, though we run into the problem of potentially abusive combos (not game winners, but ways to get around built in restrictions on cards).
I trust that it will get sorted out in a fashion that is easy to remember, and if not completely intuitive, what is good for the game.