That is not true. It is a talking point that is repeated but has no bearing on reality.
What's often misunderstood is what "fiduciary duty" means. It doesn't mean "make the most amount of money possible", it means "act in the best interest of".
Otherwise one state would have a monopoly based on it being business friendl... oh wait, maybe that is the case.
The corporate charter, and the bylaws of the corporation are all explicitly governed by Delaware law. These documents control what powers different share classes have regarding corporate ownership and operation.
TLDR: Delaware law is almost certainly the controlling law regardless of where the shareholder lives.