It's not rocket science, and it is obviously a loan. How is margin shady? This claim that it is somehow predatory or that consumers need to be protected is nonsense. This assumes that people can't do research and due diligence. If you aren't informed to make financial decisions than you probably shouldn't be trading. If you choose to proceed, do so at your own risk.
All brokerages offer margin and typically this is how they make their money, not commissions.
Margin isn't shady in the form that it takes at every other brokerage. Robinhood's Gold is shady because they make every attempt to market it as a higher membership tier, to young unsophisticated investors. It may not be illegal, but it certainly seems like a dark pattern.
All brokerages offer margin and typically this is how they make their money, not commissions.