There are no scientists now, or ever, that have ever said oil is from dead dinosaurs.
They've said (accurately) for a long time that oil comes from fossil marine microscopic plankton (largely diatoms and algae.)
There has never been a scientific theory that oil comes from dinosaurs.
For whatever reason, people think there was for three reasons:
1) When you say, "fossil" people think "dinosaurs" though only a tiny, tiny, tiny portion of the fossils on earth are dinosaurs. And the average person has such limited scientific knowledge they don't know what a diatom or plankton is.
2) An oil company developed an amusing cartoon and billboard campaign linking oil to dinosaurs, which remained fixed in people's brains
3) A collection of idiots led by the moronic Jerome Corsi, in arguing for abiogenic oil, have created an imaginary strawman to argue against, that "scientists" claim oil is from "dinosaurs."
***2) An oil company developed an amusing cartoon and billboard campaign linking oil to dinosaurs, which remained fixed in people's brains***
ESSO or HUMBLE OIL.
"The original Sinclair Oil Company began marketing the apatosaurus (brontosaurus) in 1930 and now after more than 70 years, "Dino" still remains one of the most recognizable corporate logos in the world."