This summary, authored by a law professor, takes a different view:

https://www.professorbainbridge.com/professorbainbridgecom/2...

That doesn’t seem like the conclusion of that article to me. For example, the author writes:

“The court may hold forth on the primacy of shareholder interests, or may hold forth on the importance of socially responsible conduct, but ultimately it does not matter. Under either approach, directors who consider nonshareholder interests in making corporate decisions, like directors who do not, will be insulated from liability by the business judgment rule.[9]”

This thread https://news.ycombinator.com/item?id=23393674 has a lot of quotes from primary sources and legal analysis, and reaches a similar conclusion: directors can largely do as they please.

No, it doesn't.

Acting in shareholders interest is not strictly equal to optimizing shareholder returns.

In my view corporations are meant to do what their owners want them to do. It just so happens that the vast majority of shareholders want the company to give them as high a return as possible.

However this does not need to be the case. If the owners/shareholders want they can demand the company to be responsible for the environment, to be socially responsible as well, or to do basic research instead of maximising short term profits. It just requires the majority of shareholders to want that, and right now this still isn't the case.

This is actually something I picked up from reading Milton Friedman's books, where a corporation exists to do the will of the owners/shareholders. Maybe I read it wrong but that's what I understood it as.

It’s odd that this question which specifically refers to “legal obligations” appears on skeptics.stackexchange.com and not law.stackexchange.com. But the accepted answer hints at the true position when quoting another source that says “the business judgment rule ensures that, contrary to popular belief, the managers of public companies have no enforceable legal duty to maximize shareholder value.” That is, as pointed out in a less-upvoted answer [1], there is indeed a legal duty to act in the (financial) interest of the company and its shareholders, but courts allows for some risk-taking and for value to be realised over a long period, so you can’t prove a breach of the duty solely by reference to share prices.

[1] https://skeptics.stackexchange.com/a/25118/19389

That argument is :-o levels of bad.

"If the legal obligation to maximize profit for shareholders existed we would have to develop a good definition of how is is to be measured."

Translation of this bad argument: "Everyone uses words differently, so laws are impossible."

We have almost a century of stockholder lawsuits, some successful, to show how ridiculous this argument is.

That's not the argument made in that post, AFAICT?