Perhaps I wasn’t clear enough. The defiance BECOMES disbelief. One does not stand in contradistinction to the other, disbelief (or as I said earlier, a dedication to disbelief) is actually the punishment for defiance.
I did not quote the rest of the first chapter of Romans, but perhaps you should review it at you convenience.
I don't attach as much importance to that passage as you do, but rather than explain why, I'll refer you to what I said at greater length in another thread (in posts 44, 47, and 48).