It's not about winning or losing, it's about getting "run over" by massive momentum. Retail investors move less volume and randomly take both sides of trades, so it's much less risky to trade with them. Conversely, large players can dump so much volume that they move the price against a market maker and decimate their revenue from whatever very small spread they usually collect.
> The most obvious way for Robinhood to optimize its revenue is to get its investors to make lots of bad trades.
Robinhood doesn't care whether trades are good or bad. A discount brokerage is a moving business, not a storage business (unless you count interest on cash balances, which Robinhood doesn't make much from). They make money from retail investors doing a lot of trades. Arguably that's against the interest of the investors because retail investors tend to make bad trades, but there's no malice on the part of Robinhood there. If all their clients made a lot of money presumably they'd use it to make more trades and make Robinhood more money.