Well of course that’s not true. None of them do, from the FCC to the SEC. But some do a better job than others.
FINRA (the Financial Industry Regulatory Authority) seems to do a fair job considering their financial and political constrictions, as you can see below. But out of 637,000+ brokers, they only examined 4500. Or about 7/10 of one percent. More instructional is the cases of theft and deception committed by specific brokers. They’re instructional because they all could have been prevented by more aware investors.
I invite you to explore their website at finra.org