If they are following all the rules in order to compete, which I'm guessing is they attend an American school and they are within a grade range or age range, then I don't see the problem with them competing and kicking ass. Good job to them. The American school system can learn a lot of things from other countries when it comes to education.
Same with the marathons, if they are observing all the rules then more power to them to kick some ass. When the Kenyans host a food eating contest then we can send a couple of our big boys over there to show them how it's done. Oh wait, the Japanese are better at that...
All languages have some quirk to them, it just depends what you grow up learning. The French language has a lot of rules and if you follow them you'll be alright. The English language also has some rules but more often then not you have to break them which is really difficult for a foreigner to understand. See here for some examples: https://web.cn.edu/kwheeler/English_hard_2learn.html