This is nonsense. US Soccer likely has the largest reserves of any soccer entity, and even if they are paying a full 1% management fee, that means some lucky company is making $1 million to manage this portfolio, gross. If they were giving away 20% of the upside to a hedge fund, that would be listed as their investment. I expect US Soccer pays less than 1%, but it is not worth my time to look it up. How they spend this money is a worthy discussion.
All non-profit youth clubs file tax returns if they want to maintain their non-profit status, and must disclose not only reserves and investments, but payments made to any officers and directors. So find the club IRS 990 filings that prove your hypothesis, and link them here. No investment banker or lawyer in their right mind would risk their career or license over the few thousand bucks they could make by de-frauding a youth soccer club and playing some shell game. As for the millions of dollars at stake, large clubs pull in around $2 million in fees and revenues a year, and pay out 80-85% of this in coaching salaries and field costs alone (also available on these forms to see). The balance is registration fees, league fees, and general overhead.
Most of the clubs who are not non-profits do not have boards, and are run by coaches/DOCs. Very few coaches are current or former Wall Street professionals.
You got a problem with a non-profit youth board, go join one and run a club for a while. Stop smearing those who volunteer their time, and also often donate a lot of money for scholarships -- one reason why bankers and lawyers are often on these boards. The other reason is that they need experienced people to help them comply with the reporting and filing requirements, and manage the legal risks, if they do not want to pay third parties thousands for this service.