I don't think FNC is gonna win EVERY map against DRX, hell I think they could even lose to DRX. A theoretical map veto would be something like this :
FNC ban Sunset
DRX ban Lotus
FNC pick Haven
DRX pick Abyss
FNC pick Ascent
DRX pick Corrode
Bind remains
Haven goes the way of FNC, but I think DRX might just sweep Abyss, Ascent and Corrode to win 3-1 since they have a superior Abyss, FNC haven't been very good on Ascent, and Corrode is also a weak map for them while it's strong for DRX. Even if FNC win Ascent, I favour DRX on Bind.