It makes sense because of the way the crust which is full of life is continually forced downward to be recycled.
Yes. Like a giant juicer, it squeezes the juice out of everything, which the bugs and microbials reduce to various simple hydrocarbons, and congeals and pools up. Some gets sealed in between nice leakproof layers, some not.
BUT, the mantle/crust interactions, with high temps/pressures, and a variety of molten matter can also give off hydrocarbons which would be driven upward, and pool under various non porous rock.
SO, I don't think it's one way or the other for oil creation. I think it's both.