I find this a cynical or maybe a sardonic statement.

Judgment aside, there's a cost for the society which is not borne by owners of these giant corporations. These owners have a selfish interest to propagate dubious means. With "selfish" I mean the good natured selfishness in the sense of Smith's capitalism. So we as a society should strive to charge the owners with these costs, so that products like RoundUp get uneconomical to produce and sell.

Keyword: external costs

It is, indeed, a cynical statement. But it gets to the very reason why we aren't looking closely enough at the potential social costs.

As an aside, I think the conventional wisdom reading of Adam Smith, that somehow selfishness begets virtue, was not the author's intent, and is mostly just a self-serving rationalization. At the very least, it ignores the ways that selfish action can turn toxic - deception, corruption, theft, and of course externalized costs.