well radscorpions are using sting yes.
But for example floaters are using poision gas.
I think it should be protecting from poison too.
It could be interesting to make some dungeon with radiation and poison. so Players would have to use hazmat suit with low damage resistances. So even lower critters would become serrious threat. And if armor detoriation would cause rapid lowering of both poison and rad resistances it could give really interesting factor to game.