OK, I'm going to hold forth on this one, forgive me. Maybe it should be a different thread, but the absurdity of this seems emblematic of the absurdity of our national (or maybe even modern) dialectic on "race". Rational people are sandwiched in between these two competing absurd, anti-factual ideologies. One which says, essentially, "we're all the same, there is no genetic variation in human beings", and the other which claims that the variations in the human genome are predictive of, well, pretty much everything, ever. We're different, to a very small extent. It's meaningful in some ways. People from various ethnic groups and branches of humanity are susceptible to different diseases, genetic mutations, etc. If you want to get really edgy about it, it may be true that we even test (to an extremely small degree) differently in tests which test...well, whether or not you test differently, essentially. They don't seem to test much else, by any scientific standard. But one side is ready to set up the guillotine if you remark that, hey, Ethiopians sure seem to win a lot of Marathons, and the other side will garrote you in a heartbeat if you mention that, wow, Neil Tyson is a pretty smart guy. Or what have you.
Of course the truth is that very, very few of us are "purely" anything, anymore (as if it mattered), particularly in the developed world. Go deep enough in the woodpile, and there's someone who you'd look at and say "that guy ain't from around here". But oh, Lordy, don't screw with our perception of ourselves as members of some Tribe or another, or we'll absolutely lose our poop. Maybe we're not that Evolved, after all.
For my money, call your football team whatever you like. Anyone who has half a shaker of sense will recognize that all of these terms are outdated pseudo-science. And the rest? Well, who cares? What difference does it make?