Because they are subject to a regulator and hold a license from a regulator.

Bernie Madoff's operation was also subject to a regulator and was properly registered as a broker-dealer; that did not somehow make it a regulated operation, at least not in the sense of actually complying with the regulations. Boiler rooms are also subject to a regulator (the SEC) and obviously are not regulated brokerages.

Really it sounds like this is a disagreement about what it means for a market to be "regulated" -- I draw the line at compliance, you seem to draw the line elsewhere.