Harvey literally comments are not rejecting the labor theory of value but the way it has been interpreted by certain schools of Marxism historically, he clarifies the distinction of it from a "value theory of labor" that was expounded on by people like Diane Elson, and endorses a value form that he thinks is accurate and what Marx was getting at. Marx's labor theory of value was not really his, it was derived by later writers, there are other perfectly valid derivations that look more like Harvey describes, and is still befitting of the term Marxist. I don't agree with it, I think Michael Roberts had a good critique, but he's still a Marxist.

I also see no reason calling Harvey a revisionist should be a pejorative or disqualify him from being a Marxist. Most Marxist writing is revisionist in some way at least, and claims of orthodoxy and that ones own work is the single scientific explanation is a rhetorical strategy, and not really meaningful to the content of any work that claims that..