"Cultural appropriation" is a very recently invented concern, and Harker can't possibly have had it in mind - not only was the term not in anyone's political vocabulary when he was writing, it doesn't fit into his Marxist scheme at all. Though the literal meaning of what he wrote is clear enough.

I just read the section on modes in Sharp, alluded to yesterday in this thread. He does at least try to give concrete examples, but throws away far too much pre-existing knowledge (that of the mediaeval Church and especially that of the Middle East, India and China) which could have been very, very useful to his project. I'd definitely score that one up to ideological blinkers.