I think he was thinking that you were asking why can't you Enchant Armor with the Weapon Enchants, not the Fortify One-Handed Enchant. Since "can't hit them with it" doesn't really apply to what you can get Fortify One-Handed on: Rings, Necklaces, Gloves, and Boots.
There's really no cut and dry "Enchants like this go on these slots and Enchants like these go on these slots" besides listing the majority of them. Exceptions being all the Fortify Spell Schools are Rings, Necklaces, Helms, and Chests (Fortify Spell School + Magicka Regen is Chest only), all the Fortify Weapon/Armor are Rings, Necklaces, Gloves, and Boots (Fortify Archery is -Boots, +Helm), and all the Elemental Resists are Rings, Necklaces, Boots, and Shields (Poison/Disease is -Boots, +Chest, Magicka is -Boots).
Edit: In retrospect, that is the majority of them I suppose :/