I don't see anything in the parent's comment indicating that he supports unfettered self-interest.

As far as I can tell almost everyone nowadays supports the idea of having markets which are partially free, but subject to some regulation (which was Smith's position). Hardcore Rand and Marx devotees are on the fringe. We are all just debating the degree and character of the regulation.

We debate within Smith's world because he was right and it's easy to see, free markets tend to produce big winners who have so much wealth and power that they eventually find a way to corrupt the market. Regulation should focus on this basic problem: there's no great social upside to a $100B company becoming an $200B company, whereas there's lots of social upside to promoting lots of competition, small firms, and a sense of fairness so that everyone can pursue their self-interest.