I don't really see the issue unless there were incentives set up to encourage this and it wasn't properly disclosed.
Usually when you trade with a bank desk you know that they're betting against you because they're the ones on the other side. If they weren't doing that then you'd always have to wait for a customer to take the opposite bet, but the market might move by the time such a customer appears.
Generally you don't want people in Honest Goldman's Sound Financial Advice Inc to know what people in Goldman's Shady Shell Fund Ltd are doing and vice-versa.
As the article tells us, a lot of athletes walk into meetings with their advisers and just get snowed by a bunch of jargon they don't really understand. They're not necessarily sophisticated investors who even know to ask these questions
I agree that there are issues with unethical financial advisors and retail customers. OP linked to an article about the wholesale "professional" market where the same rules don't and shouldn't apply. I'm saying that as someone who's been both on the bank side and the customer side.
Usually when you trade with a bank desk you know that they're betting against you because they're the ones on the other side. If they weren't doing that then you'd always have to wait for a customer to take the opposite bet, but the market might move by the time such a customer appears.
Generally you don't want people in Honest Goldman's Sound Financial Advice Inc to know what people in Goldman's Shady Shell Fund Ltd are doing and vice-versa.