I don't agree with you. There is a different utility to commodity futures, for example, than to bets on horse races or blackjack games. Derivatives allow tailored hedging of real-world risks. The regulatory stipulations are different, especially for dealers, and there is a far larger opportunity for people with predictive skills in the derivatives market.
> And this wasn’t manipulation, just two parties doing their fiduciary duties.
By this logic, any profit from market manipulation would be justified because it generates a return for investors. Yet the reason these behaviors are prohibited is because they make the market worse for everyone, arguably including the long-run returns of those very same investors. "Is it beneficial to my investors" is a very poor test to answer the question, "is it manipulation?".
