Fair point, in his defense I think most of that is directed to the online/intellectual left figures he singles out for criticism - Chomsky, Graeber, ML, J.Cook, C.Johnstone etc, but yes there are other kinds of leftist. Semantics again
Not going to defend Blumenthal over GBD. Here's Nafeez Ahmed's original 2020 report tying it to Koch bros interests & climate denial groups: