It was hax like that, yeah. XD Probably because they didn't want to create unwinnable battles in the game by first taking away all of your elemental skills and then giving you enemies you couldn't possibly hurt? MegaTen's big on challenging, but there's a difference between difficult opponents and an impossible victory...
Breaking resistance to ailments? Some individual skills do that, but there's no universal skill to do so. *Blinks* I wouldn't expect it to work on bosses, though, and quite a few characters will recover instantly, so... uh... yeah.