"However, I wouldn't give a dime a dozen for the political songs of which, he tells us, it was his aim from the 60s to the 80s to write at least ten each month."

Yes, but that basic complaint has little to do with politics per se, and more to do with the law of diminishing returns.

Writing ten songs a month for months on end about any subject at all - love, sex, work, food, dancing or indeed politics – is a tall order. Unless you are a superhumanly versatile songwriter. One great song is always better than ten so-so songs.