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.