You are boldly and confidently at odds with the usual explanations of the formation of oil:
* https://energyeducation.ca/encyclopedia/Oil_formation
* https://en.wikipedia.org/wiki/Petroleum
these other sources all assert that
The origin of fossil fuels is the anaerobic decomposition of buried dead organisms, particularly planktons and algae.
I think they are conflating Carboniferous Period / white rot slowing _coal_ formation with Oil formation.