I find the @nytimes guest responses to Friedman's 1970 essay don't do justice to Friedman's argument. So I picked 5 passages from the essay that I think summarize it well (THREAD):

(1) "[A corporate executive's responsibility] is to conduct the business in accordance with their desires, which generally will be to make as much money as possible while conforming to the basic rules of the society, both those embodied in law and . . . ethical custom."

(2) "Insofar as his actions in accord with his 'social responsibility' reduce returns to stock holders,he is spending their money. Insofar as [they] raise the price to customers,he is spending customers’ money. Insofar as [they] lower wages . . . he is spending [employee] money."

(3) ". . . suppose he could get away with spending the stockholders’ or customers’ or employees’ money. How is he to know how to spend it? . . . How is he to know what action of his will contribute to [any social] end?"

(4) ". . . there is a strong temptation to rationalize [profitable community-oriented] actions as an exercise of 'social responsibility.' . . . [a] way for a corporation to generate goodwill as a by‐product of expenditures that are entirely justified in its own self‐interest."

(5) "The political principle that underlies the market mechanism is unanimity. . . . The [one] that underlies the political mechanism is conformity. . . . the doctrine of 'social responsibility' taken seriously would extend the . . . political mechanism to every human activity."

There you have it. Friedman:
- recognizes ethics as well as law place obligations on firms
- is concerned about managers' knowledge & incentives to abuse their "social" mission
- shows many "social" actions are profitable as well as doing good

& he:
- worries about extending political decisionmaking to more & more areas bc it'll enforce conformity instead of freedom