A melee character needs only a weapon to do damage - period. The amount of damage is defined by the weapon.
A ranger character would, by your desire, need a weapon - which again defines the damage - and then on top of that normal ammunition, which adds exactly nothing to damage, therefor placing limitations on ranger weapons that do not exist for melee.
Larian has placed limitations on all ammo that causes ADDITIONAL damage, over and beyond that defined by the weapon - thus placing it on an equal level with melee type weapons.
Personally, I find this to be balanced, fair, and appropriate.
If you want to place limitations on ranged - must have a fresh, normal arrow for each use, then how about similar limitations on melee - must re-oil and clean your melee weapon between every swing - requiring a fresh oily rag for each cleaning. I'm betting you aren't in favor of that one.