I agree that many people perceive this as an absolute truth, and I have to reluctantly acknowledge Milton Friedman's success in completely changing the narrative around corporate responsibilities. I don't think that the adoption of this narrative is due to the Internet though; the original Supreme Court decision of Dodge v. Ford legally enshrined it and the narrative has been actively taught for a long time. I know that I took it at face value for a long time as a result of my education along with the overwhelming share of my peers so I'd say this has been pushed by a broad segment of society.

At present we do rely on shareholders in different parts of society to fund new ventures -- most of us are here on HN because we worked at a VC-funded startup. Shareholders should get paid out. But workers have a stake in a company, the community has a stake in a company, and society at large has some small stake in a company. We shouldn't select shareholders as the main voting party in the operations of a company when the impacts of company operations are so much wider.

For good examples of companies whose impact was much larger than the shareholders, see also: DuPont/Chemours with PFAS, the manufacturers of CFCs, oil companies, etc.