That's because WoW was built with PvP in mind (PvP servers, able to flag for PvP on PvE servers, skills balanced around PvP and PvE(supposedly)) and has a comparatively huge PvP community when compared with FF14 that wasn't built with PvP in mind and doesn't have a large PvP community.
Though, I really wouldn't want WoWs PvP community anywhere near this game. Terrible, terrible people.