Because there is another group that's putting up all the work. In startups, that work is generally more intense and risk laden, which is why employees are offered shares as part of compensation. Otherwise, why would they be offering shares? Both groups deserve protection.
The SEC was created so that people couldn't swindle each other in a legal manner. It works to some degree for investors who are, by the definition of these types of investors, rich ($1mm in assets or $200k/income). But it clearly isn't working for the people doing the work.
So our system protects the rich, but not the people who apply a trade. If you think that's ok, fine. But I find it terribly unfair.
Joint stock companies exist as a result of legislation, the separation of capital and management requires courts for mediation. I can't see why someone wouldn't support changing it to be more equitable to all involved, especially if it is done based on merit (where labor and capital are both weighed as equal inputs at the time of distribution of large liquidity events)