One of the biggest issues right now is that we have to worry about what the future will look like? That's exactly what is meant with externalities as well, you profit from your behavior without having to compensate for or deal with the consequences. You're redefining the very definition of an externality.
"The Environmental and Energy Study Institute reported that direct subsidies to the fossil fuel industry totaled $20 billion per year, with 80% going toward oil and gas. In addition, from 2019 to 2023, tax subsidies are expected to reduce federal revenue by around $11.5 billion. Considering that production subsidies grew 28% between 2017 and 2019, the United States will be under a lot of scrutiny from other countries wanting to see evidence of reform before making their own commitments."
Perhaps you can point the exact text for the subsidies explicitly for US gasoline which are not related to how the companies subtract their costs to determine their income. There might be something for the other fossil fuels, but I see nothing as far as oil/gasoline.