USPC is a private company, and while the rules are generally "unwritten", there are certain things that they may decide not to print. If I recall correctly, the original design for the Ace of Spades on E's Ghost Deck had more detailed snakes. USPC had an issue with this for some reason, so the snake artwork was toned down a bit.
As a private company that promotes a family brand/product line, it's totally their prerogative to rufse to print whatever images they like, whatever the reason may be.
In the case of this particular deck, we don't know exactly why BBM was turned down. And odds are there is a company out there somewhere that would print it. Alternately, I'm sure USPC told BBM what changes they could make to the deck in order to make it "acceptable".