According to this logic, any comp could just put "Nationals" in their name and turn an ordinary comp into something only for American teams. If an international team manages to raise the money and wants to enter one of your nationals, you should treat it as a privilege rather than something that might diminish the legitimacy of your "nationals". Of all the 78 nationals they could attend, each kid and their family saved up thousands of dollars (if they're from anywhere but Canada) so they could come and experience Cheersport, or NCA, or COA, something you all get to experience every season. Be thankful that you get that opportunity on your doorstep and welcome these kids with open arms. More often than not, they don't have proper facilities to train out of, they've never performed on a raised stage with lights, they might not have full team level skills, but they have the heart and the passion. One little Australian team got the opportunity to attend Duel in the Desert (and placed!) and it was the most inspiring and amazing thing in their entire little cheer lives. Then again, I guess Duel isn't a "nationals" so it's not an issue for them to attend that comp, right?
Long story short, not letting international teams enter US nationals isn't going to make the 50+ national events any more legitimate. It's the fact that any company can call themselves nationals that's diminishing their legitimacy. /endrant