So, every system, mutual fund, hedge fund, etc. is snake oil because they have clients? Because YOU wouldn't take on clients if you knew how to trade...except your Mom and Dad.?
I think he is saying that some people may try to convince others to develop systems in their platform with the objective of profiting from them. I think Quantopian advertises this openly and promises a cut. They are sincere about it. The question is how long the edge if any will last when the algo is shared by commercials.