What won’t be obvious from the press coverage if you don’t compete in USATF events is that under USATF Competition Rules, you cannot compete in a National Championship if you are not able to compete in the World or PanAm Championship Event that the National Championship selects a team for.
The athlete in question recently became a US Citizen and because of the IAAF rules is not qualified to compete in the World Cross Country this year, thus he is not qualified to compete in the US XC National Championships.
It’s created a bit of controversy here, but I don’t think anyone is out to get the guy. Those are the rules.