Unless I misunderstood him, he's not complaining that people can make their own decisions with their money, aka that anyone can use this service even if they're not well versed in that field, he's complaining that Robinhood entire business model is based on pushing the very users who don't know how to use it in a sane way, to do it anyway. That will be the company's lifeline, as its way to make money.

I can see the benefit in making it easier for people to get access to things that are often hidden behind layer of complexity and "need an in", but I can also see the perversity of building a business where your money making system is "put debt on people who don't quite know what they're getting into". The point is not that they allow it, it's that they have a direct incentive to make it happen as much as possible.