Some of those are because international standards (the military and ammo, although the US military uses yards more than kilometers, but they do use both, probably because of international influence). Some are because science is run on metric (pharmacists).

Litres though, yeah, idk. I’m assuming it’s because it’s easier to make a bottle in Litres and sell it around the world? Litres predate metric too, so it could be because of that? I never see poured liquids measured in Litres though, only bottles. Usually it’s pints or fluid ounces.

I do have to congratulate illegal drugs for teaching metric to Americans probably better than our schools though. It’s an interesting dynamic.