I would agree with
@Pekelo... I think he's saying that the local market is the domestic one. And as a large oil producing country, Mexico is likely to set the prices for that, or at least they could/should... just like Venezuela does. It's not really subsidizing, but there is an opportunity cost indeed, by not pumping all oil at higher prices abroad.
But we in Australia are having a similar discussion regarding our gas supply. We export a lot, probably at low prices... I heard Japan for instance makes more money on Australian gas than we do on that export to Japan. But, we could hit a supply shortage due to oversees contracts... than there should be a backstop for domestic use, likely at lower prices....
So I would think Mexico would do the same. They would have some qty of oil dedicated for domestic markets. Any producer should do that.... I'm not sure about petrol prices in Mexico, but I would think they are significantly lower than the US.