You might be on to something there. If they refuse to be honored by being named by sports teams, name the teams after European groups, including various tribes and ethnicities of old Europe: the Franks, the Saxons, the Vandals (double meaning there), the Sorbians, the Etruscans, etc. You could have some cool outfits too.
My high school’s teams are called the Comanches. As far as I know, there has not been any effort to change that. If that ever happens, Franks would be the perfect replacement because the French settled that town in 1699, and there were never any Comanches in Illinois.