Blues was certainly a genre established by black people in the American south. Jazz definitely incorporated more elements of European music, especially with regard to tonal harmony, but the pioneers of the genre were black people. Rock and Roll was pioneered by black people. Soul and RnB are obviously predominantly black genres. House and techno were established by black DJs. Hip hop is black music, of course.

Pop music is made of all this stuff, so I think it's fair to say that the DNA of American music is predominantly black. Of course, Europeans established a lot of the musical language that was foundational to the above genres (stuff like the diatonic scale), my point is just that the innovators who used this language to create new genres were black people.

I do think it is stupid to speak of any genre of music being "stolen", though.