I thought it might be something like that. I'm not entirely sure why they're so worried about "brokers". They got paid by Amex for the miles (quite a bit in fact) and it's not like they would ever let me redeem for seats that they thought they could sell, so it's free money for them.
Am I permanently out of luck? I'm still hoping American Express comes through and helps me get these miles back, if Flying Blue is determined not to let me use them