The reason is that the medicine might be worse than the cure. I don't like fraudulent accounting and securities fraud, so I'm glad we have the Sarbanes-Oxley law which helps to prevent it. However, SOX now makes being a public company more expensive and complicated, thus a lot of private companies decide they don't want to be public. This created new problems, for example billion dollar companies that choose to remain private.

I don't support companies being "shady". I wouldn't work for a company that didn't give me all the information I needed to evaluate any stock options. However, unless you are giving me a specific law or regulation that intends to fix the problem without creating many more, you don't know if the solution is any better than the status quo.