You know, I was going to make a topic on fairy, but meh, guess I'll post here.
Fairy:
Dark- One, Dark needs more super effective types than only ghost and psychic. Two, due to the advent of Christianity, fairies are considered demoted angels who were not good enough for Hell. So as darkness is too good for them, they would be overpowered by it.
Poison- Some fairies are nature spirits, as such, pollution would kill them.
Ice- Same as Ame's reasoning. (snatcher D=<)
Steel- Fairies played a huge part of the past as deities. But with science on the rise, folktales are just tales. And steel is considered futuristic.