Can you explain, conclusively, why it is that oil that comes from plant life and whatever other conditions that cause it to be in that form, is necessarily *created* by life, and not simply left over? Such that those same conditions couldn’t create it from hydrocarbons that aren’t a result of organic matter decay?

You mention some well known points that are relevant, but then the conclusion doesn’t follow. That “oil would not have formed prior to the existence of certain kinds of life” is not supported by the fact that organic matter can turn into oil if the conditions are right.

Again, my analogy. This would be like saying water was created by life because it seeps out of organic matter. The claim that it’s *created* solely by this means, and then explicitly adding certain conditions of pressure and temperature, simply is a guess. All of those other things can be true, while hydrocarbons could still create oil under similar conditions of pressure and temperature without life having been involved at all.