I think you're misunderstanding the threat model. It's designed to protect unsophisticated investors from fraudsters, not from the investors themselves.
I don't think this is true. A clear example is startup stock-options. It is legal for the company to give you that as compensation, you historically get taxed for that compensation, it is legally mandated to get appraisal by a third-party company, but it is generally illegal to offer them for sale in the public.