Can I try to find some middle ground on this issue?
I think most people agree that if you are willing to serve in our military and become a US citizen, then by all means, you should be allow to represent us as Americans on our national teams. I 100% agree with that. Citizens can run for their national teams. People need to stop whining about it. Alan is right.
But it is off-base when people act like there is "no difference" between a person who moves here as an adult (college-age or up) and an American-born runner who has lived in our (sedentary, fast-food, car-based) culture for 18 years and somehow goes on to succeed.
And this impacts who we identify with. I am 175 lbs., 6' tall, and grew up eating American food. I can relate to other Americans who are like me more. If you are Joseph Chebet and you weigh 118 lbs, stand 5'2 tall and were born at 7800' of elevation, I can't relate as much. It is not racist to say I don't relate to that. It isn't about skin color, it is about how we grew up.
For most of us, it isn't about race because we don't consider Pappas to be Greek, Parsons to be German, or Klosterhalfen to be American even if she were to get US citizenship. People like that are US citizens without being Americans. Does that make sense? You can get Italian citizenship without becoming Italian. Obviously.
p.s. My wife is a US citizen but doesn't think of herself as American because she didn't grow up here. There is a difference, and acknowledging that reality isn't "racist."