If you assume that everyone is an informed, rational actor, then the rules are silly. I would argue that this is an incorrect assumption.
Really I think it's just too hard to scale the protections and legal mechanisms. ICO solves some (not all) of the scalability problems.
ICOs, penny stocks, and other scams being advertised in the cash4gold shops with a pushy salesperson? Yes, that'd be a problem, and the obvious result of no regulation.
In the EU, there are a lot of regulations around marketing securities to inexperienced investors, and if you screw up, you are liable.
What you're not taking into account is macroeconomics. When you let anyone do whatever they want, it is very likely that the rich will get richer (because they are more informed) and the poor will get poorer. And with that comes corruption. That's why the government steps in to break off organizations that become too large and make sure things like antitrust don't happen.
If you think the society is unjust, first try to learn WHY things work that way, that way you may either come up with a solution that can solve it, or go build your own nation, or at the least understand what's going on.
The some obvious examples are environmental and food safety. Another is financial regulations to prevent "too big to fail" institutions from taking wild risks that result in bailouts with taxpayer funds.
A producer who skimps on food safety can save costs, and the externality is people getting sick, through no fault of their own.
And if your vegetables being "contaminated in ways that you can't reasonably detect" isn't a case of you not knowing what is good for you, I don't know what is.
we have regulation to prevent people from being misled.