As soon as you're public, it inevitably introduces strong pressures to pursue profit no matter its cost, as it decouples the negative social externalities corporate actions can cause from the profit made from those actions.
No it doesn’t. There is no threat to google given that the majority voting control is held amongst the founders. Same for Facebook. There is no risk of a hostile takeover or being voted out by public shareholders.
Shareholders have plenty of ways of impacting corporate direction that fall far short of hostile takeovers. E.g. lawsuits; the very fact that a public company has to provide more information about its finances. There's a reason Ruth Porat was brought on after IPO and not before.
How is there more coupling between a company's profit and negative social externalities resulting from its actions when the company is privately-owned? If anything, I would think there's rather less coupling in privately owned companies, as a public company is at least forced to be somewhat transparent, publish SEC releases, subject itself to audits, etc. For example, unlike a private company, it wouldn't be possible for Google to engage in a material transformation of their business without accounting for it publicly towards their shareholders.
This is the relevant part.
As soon as you're public, it inevitably introduces strong pressures to pursue profit no matter its cost, as it decouples the negative social externalities corporate actions can cause from the profit made from those actions.