As I understand it, Loki is and always has been educated purely as an Asgardian.
The techniques he's learned are Asgardian techniques, taught by Asgardian teachers (and possibly some from other realms, like the Dark Elf in the Thor animated movie). He has a real affinity for the skills he's learned.
By and large, Frost Giant society does not encourage thought or magical skill - they tend to develop their natural affinities for ice magic, if that innate skill is potent, but otherwise they don't spend much time studying magic at all.
Loki is certainly evidence that
Frost Giants CAN learn such magic
but that doesn't necessarily lead to the fact that there ARE Frost Giants who have. As far as I know, there are no Frost Giants from their native society who are proficient in the arts of Illusion, as Loki is.