It’s not that black and white. Over the long term, shareholders are better off if the journal can maintain a reputation of impartiality, so it would be difficult to prove mismanagement in this case. It’s like when Apple cared more about customer satisfaction and doing the right thing than short-term ROI. Sure, shareholder could sue, but they would likely lose.

The idea that a company must only do what brings shareholder money immediately is a meme that is widely propagated by a certain class of people who stand to profit from it, but the law does not impose that behaviour.