That was one complaint I had as well. I didn’t find the game difficult, but I was draining resources a lot faster than I liked. I ended up in a long series of shootouts at one point in the game and was not gaining ammo as fast as I was using it.
Turning the game to an easier difficulty made the enemies less spongy, and I was using less ammo as a result, but it doesn’t feel like a good use of the difficulty slider.
I would prefer having enemies remain easy to kill, but having higher difficulties just make me easier to kill as well. If all the difficulty slider does is give enemies more health, it’s not really a difficulty slider, it’s just a tedium slider.