I'll confess to not having read McCalmont's essay all that closely, in part because I think the very things that make it such a grand challenge to the field are the reasons it's not actually as clever as it thinks it is. I've mentioned his outdated conception of steampunk, but the way he treats China Miéville is also instructive, and relevant to the things he claims to want from SF. The City & the City
is indeed socially conscious and politically motivated, but it's not the exact kind
of that that McCalmont wants, so it's a "sterile fantasia" and so forth. Piffle. I don't even like The City & the City
that much, but the book's failures have very little to do with its not being a precise kind of Marxist-inspired fiction. (I should say for the record that I have no particular objection to Marxism as an analytical tool.) Miéville's Iron Council
(which I haven't read), a novel so politically engaged that it drew a fan backlash, comes in for a similar slating in the comments, apparently for daring to acknowledge that moral ambiguity still exists in situations where one political structure is obviously preferable to another. There's criticism that demands greatness from fiction, and there's criticism that mistakes a personal set of values for such greatness, and I fear McCalmont tends in that direction. Exacting standards are not the same thing as high ones.