There is a niche market here
1) Set up a brokerage firm that does super clean practices, one that doesn't reveal stop loss information to the rest of its clients, one that doesn't allow its clients to do shorts hence doesn't touch client shares by lending them. I think majority of retail or mum and dads would use your firm as they only want a simple investing strategy.
2) another niche market is for an existing broker to commission a software developer to come up with a software that creates fake stop losses for its clients in order to confuse or frustrate everyone else trying to manipulate. This way, a broker doesn't start from scratch in #1 but will thrive on what many investors want.
What do you think, can a broker thrive in super ethical practices?