NS: Japan beats USA 41-20 in international U-20 football tourney

It’s bizarre to me that these are the best players we can send. Are there rules saying the pool must come from Division II/III collegiate athletes?
I think it's more who's willing to go, rather than who can be sent. Your average 19 year old football player in the U.S. is a sophomore in college. The ones who are good to great are usually in big college programs and looking at the NFL and $$$, not some cockamamie tournament. A lineup that includes all the sophomores just from LSU, Alabama, Michigan, and Ohio State will murder anyone in this tournament.