Maybe you can work for a non-profit if you're lucky, but how many are there out there that pay market rate?
No. That's a misconception. Corporate directors are required to act in the interests of the shareholders, but they have a lot of discretion in determining what those interests are and how they are to be served.
Here's a reference from a decent law school: https://www.lawschool.cornell.edu/academics/clarke_business_...
I agree that there's still a lot of lee-way in that, like giving an employee a bonus might hurt shareholders directly in the short-term but you can claim it increases productivity and so is a good decision. You still have to justify all decisions in terms of value to the shareholders though. If you (as CEO) decide to just stop all work and spend every day at Disneyland until the coffers are empty you can be sure you'll lose that suit. And when every single decision has to be viewed through that lens, you aren't able to directly do real good for the world, just indirectly.
That's just the excuse the CEO's mouth pieces trot out when the company is doing stuff that is shitty and sociopathic. You'll notice the CEO has no problem getting the company to do things that enriches himself at the expense of the shareholders.