I love the way school choirs can cross boundaries.
Whereas crosstown sports rivalries can devolve into shouting matches and an assumption that the other community is somehow less-than, you will often see crosstown choirs joining together for festivals, sharing days, and other opportunities to sing together.
I think of it like the gradations in patriotic spirit:
Patriotism: I love my school, and people in other schools should love theirs, too. (This is where many school choirs land.)
Nationalism: I love my school and it is de facto better than other schools. (This is where many high school athletic teams land.)
Jingoism: I love my school and all other schools are de facto bad schools. (Some school athletic teams land here, and so do a significant number of fans of pro sports teams: “Not only are the Red Wings the best, the Blackhawks suck.”)
School choirs give students the opportunity to practice patriotism in a world full of scholastic nationalism and jingoism. One more thing to love about them.