“Self-regulation” in a corporate-state context is not the free market. The oil companies reportedly opposed government regulation supposedly intended to prevent spills, saying they could monitor themselves. They prevailed in that contest, but although new regulation was held in abeyance, pro-industry intervention dating back many years was never repealed.
So the choice has been between self-regulation and government regulation – in the existing corporate-state context. That context includes limitations on liability from spills and years of subsidies (implicit and explicit) and other anticompetitive, discipline-weakening interventions. Yet the choice is described as between the free market and government oversight. In fact, the free market is not one of the choices offered, but the two main political subdivisions have an interest in making it seem that way.