To summarize my objections, it seems like a “punish the shareholders” strategy has at least three problems:
1. Punishing shareholders doesn’t sufficiently discourage corporate management. They are usually fine even if the stock price takes a hit. The fact that corporate management may not act in the best interests of shareholders is a known example of the Principal-Agent Problem.
2. Shareholders might not know that bad behavior is happening, and even if they do, we want to discourage bad behavior that regulators might not find out about, and before it happens.
3. Many investors are not actively investing, but using robo investing services like Vanguard for their 401k. That means that even if you’re technically an “investor” you’re not actively investigating companies for fraud.