You are entirely correct: the notion that classical music is a somehow a superior genre is to the large part class related,
Classical music and opera have always been associated with the upper classes, while blues, jazz and their derivatives .have their roots associated with an underclass (slavery). Folk, bluegrass and Country have ties with the working class.
I don’t see any objective basis for this assertion whatsoever - good music is good music, period. Pure transcendent magic can be found in all genres, as your YouTube playlist amply demonstrates.