That would certainly be the case when considering the putative origins of older material, but in fact the majority of songs found in tradition are not very old; many began life in the theatre, music hall, vaudeville or minstrel show, and can in many cases be traced to their original writers. It is equally true that a great many songs circulating at present in the early stages of aural transmission were written by people who are still living or are only recently deceased; and are beginning already to acquire false attributions.I do not see how establishing correct attributions or clarifying the history and origins of a song, where this can be done accurately, can reasonably be considered nationalist, let alone racialist. Perhaps some academics, in America and elsewhere, are over-compensating for the preconceptions of their predecessors; this is normal, but can itself be a manifestation of political agendas quite as destructive of objectivity as those which they have rejected.
It is all too easy to impute ignoble motives to others with whom one disagrees; harder, but more worthwhile ultimately, to approach even subjects about which one feels strongly, with a reasonably open mind.