I actually agree with the law, I'm making a statement about cause and effect, and inherent vs. instrumental values. The law that requires CEOs to increase shareholder value is valuable because it leads companies to satisfy customer desires in the most efficient way possible. If it didn't lead companies to satisfy customer desires efficiently, it should be eliminated.

The problematic part is when you get that causation mixed up and argue that because CEOs are required by law to increase shareholder value, the government should help them, eg. by protecting them from competition. Because customers are best served by robust competition between businesses. Shareholder-value laws, antitrust laws, and intellectual property laws are all tools for this purpose. Just because CEOs should maximize shareholder value doesn't mean that government should pass laws that make it easier for them to maximize shareholder value, particularly if those laws are at the expense of consumers.

(And I realize that points have sorta become twisted around, such that it now seems like I'm arguing against myself up-thread. It's complicated. Basically, government should enforce level playing fields - it should make sure that products compete on their own merits, and not on the basis of their success in other fields. Cross-subsidization, like what Google does on a massive scale, is a tricky area. It's wrong if the company uses it to enter a market, dominate, and then jack up prices. But it's fine if the company uses it to enter a market, dominate, and then keep prices low.)