That's very interesting. That passage you highlight from the liner notes stood out and remained with me as well when I first read it (albeit via the early 90's cd issue ). I often recall it in my mind when I think about things related to the music. Certainly the music isn't ambitious in the way so much Jazz was/is, but it ain't easy to learn to play either. It's still really the earthy side of Be-bop (or at least Babyface is - the music Hobsbawm had in mind might be from closer to the R&B spectrum perhaps? Who is Marlowe Morris MG?)
Hobsbawm seems to be from an earlier generation of Left wing thinkers that I know not much about, but I am getting the feeling he was like a 60's Slavoj Zizek perhaps, in terms of being a kind of Left wing public intellectual.
That quote made a big impression on me as well, but I feel somewhat saddened that such a basic recognition of the basic humanity of the whole thing inevitable became a political statement.
Not saying that I don't understand why it was, but geez, people going out for drinks and dancing and having a boisterous good time to the accompaniment of music of a similar quality, that's a pretty basic human activity, It's pretty damn depressing to think that it took a "political statement" or whatever to see it as simply as it was.