The board believed (quite reasonably) that Elon had the power to determine the trajectory of the stock over the next 5 years, and they acted on that belief by tying his compensation to particular stock goals. The board then put that compensation plan to a shareholder vote, and the shareholders approved it.

The stock hit those goals, and Elon got paid.

Then one guy with 9 shares said it's not fair, and got a judge to agree.