The problem is the US is grandfathered in without staying inside its TLD. This was manageable when it was just .com .org .net etc. but now ICANN has abused this position to mint thousands of new US TLDs outside of .us. If they were inside .us this would only be a problem for whoever runs .us but because they are top-level it makes it difficult to have a decentralised root zone and not just rely on what ICANN publishes. Which is part of the point I'm sure.