Are they (Flybe) Nuts? There are still many unserved niche routes they could serve out of MAN (Seville, Lyon, Bordeaux or even the RYR vacated Bremen) - would make more sense than going head to head with KLM/EZY on AMS or the Lufthansa DUS services.
Even if they carry full loads to/from AMS I can't see how they are going to make any money out of it.