>Isn't it the case that public companies owe a primary legal/fiduciary duty to shareholders

The shareholders own the company. It is their property. They paid for it, they own it, and likewise they can do whatever they want with it.

It would be crazy if I proposed you let me drive your car to work everyday. Why? Because you own your car, it's your property, and it works for your own interest. Basically every human agrees with this logic, but somehow "the company is just focused on pleasing shareholders" escapes this.

This is not at all how share ownership works. You don’t have partial title to a corporation by owning shares.