You are failing to understand the information component again. Insiders can definitely trade. The low-paid worker and CEO can trade just like outside investors.

You are failing to understand the information component again. Insiders can definitely trade. The low-paid worker and CEO can trade just like outside investors. But the CEO is under much closer scrutiny and thus usually have regular stock sales so that they can claim "I have been selling 1,000 shares every month for the last 3 years" when faced with criticism. Again, the low-paid worker is free to trade whenever. But if the SEC spots an someone who consistently gets outsized returns in peculiarly timed trades, they are going to investigate. That person better have no proof of material non-public information at the time of those trades.