My colleague Tom Baker linked me to this story on the Jews, Muslims, Sikhs, and other minority religious groups taking special rooting interest and pride in the Olympic success of their co-religionists, even if they are competing for other countries. The author seems surprised by this, although I am not sure why. American Jews always have been very conscious of the existence and success of Jewish-American as well as Israeli athletes (while never being afraid to recycle the old joke "Do you have some light reading? Here's a pamphlet of great Jewish athletes"). What is new here, if anything, is the way that other religious groups in the U.S. are catching on.
For what it's worth, my sense with Jews and Jewish athletes is that it always has been more ethnic/cultural than religious. People knew gymnast Aly Raisman is Jewish because of her name and her floor routine done to "Hava Nagila." The issue was never whether she was particularly observant (although her rabbi is quoted in the story, so we somewhat know), but that she identified as Jewish. That has always been enough.