Musical people make music. They don't just put earbuds in, see. They make it.
Do our people stop and sing with drummers on the street, as in Africa?
Do our people sing in pubs, as in the UK? Or sing anywhere? We don't sing the National Anthem. We don't even sing "Take Me Out to the Ballgame", which isn't super easy but not nearly as difficult as SSB.
I don't see Americans gathering instruments together as a matter of course to make music. We give our kids lessons and take band in 6th-7th grade and then forget it. I stand by what I said absolutely.
Apparently your sporting events preferences are horse races and gold tournaments. People sing as every baseball and football game I have ever been to.