Question

why is jazz called america's music

Answer 1

Jazzers call jazz "America's classical music" because they have an inferiority complex. Jazz grew up in a brothel, was a courting aid for the first 30 years or so of its existence, and then went recherche and arty (about the same time classical music did). It's "classical" only in the sense that it has a tradition and a performance practice. But it's primarily a non-notated tradition, seldom has motivic cohesion, stopped being contrapuntal by 1930, and has very little in common with classical chamber music. That doesn't mean it's "bad" (unless it's bad jazz) but it's not at all the same thing.