But they didn’t intend to, right? If I steal money from a broker’s desk drawer and use it to do dumb futures trades, surelt that’s not a regulatory violation on the broker’s part.
Great case to make that you are so incompetent as a broker-dealer that someone was able to extend themselves 250x leverage on the margin you extended. That's how you lose your broker-dealer license, which means your business dies if you're Robinhood (unless they're only going to offer a cash management account, which I guess might be a thing? even Credit Karma and Personal Capital are offering one now). As a broker, risk management is your job.