It turns out that a fossil isn't "a thing turned to stone", but rather, "a thing dug up". I'd not realised this until earlier today myself.
Fossil fuels are fuels that are dug from the ground, rather than harvested from plants (as with wood or olive oil ... itself the original "oil") or animals (as with animal fats and oils).
Effectively, the word fossil has done something of an orbit such that an attribute used to describe an object ("dug up" -> petrified remains of plants and animals) came to be ascribed to the word itself, such that "fossil fuels" comes to be popularly interpreted as "remains of ancient plants ... or animals" rather than "dug up fuels".
I wonder if this is it - kids making logical inferences to connect ideas in school, and not being given quite enough information to realize there’s a gap there. And then they think that that’s ‘what they were taught’, even if no teacher or textbook ever actually joined those dots up.
Similarly, I think a lot of people think dinosaur fossils are all dinosaurs who died when they went extinct, because if fossils are dead dinosaurs, and dinosaurs are famous for dying out, those must be connected, right?
Whereas of course dinosaurs had actually been dying (and starting on their way to being fossils) for millions of years before the extinction event which… actually stopped them from dying any more.
I know I assumed Fossil Fuel = meant the fuel came from fossils, and the first thing that comes to mind when I hear "fossils" is dinosaurs.
I just never thought to look further than that.