show me the criteria where it says flat looking backs are to be frowned upon lol keep grasping at straws you need every angle you can get real or not 
the fact that you would even state something like this shows that although you can read the criteria as they are written, you truly have no understanding of what they actually mean in practice...

your reading comprehension skills have been criticized before, and its not hard to understand why...
so, lets see, so far the list of things that are "meaningless" in bodybuilding competition just got longer.
it now includes, (according to the dorian side):
-taper
-vascularity
-striations
-arms
-flatness

like I said, what will be next?
muscles?

you truly have no idea how bodybuilding is actually judged do you?
note: not how it is written on paper, but how it is actually judged in practice. There is a crucial distinction that you are totally missing.
dorian would lose, for many many reasons all compounded to amount to defeat.