It's high praise indeed, but I think that can hold its own to a similar statement made by Pavel Florensky, a Russian Orthodox priest, scientist, and Byzantine art historian who was killed by Stalin's henchmen in 1937:
"What would we say of an ornithologist who, instead of observing birds wherever possible in their natural habitat, concerned himself exclusively with collecting beautiful plumage? The natural scientists of our day have clearly understood the importance of studying nature as much as possible under concrete natural conditions... But for some reason this same concept, which is of infinitely greater importance for the study of mankind's spiritual activity, has hardly been put into practice..."(Beyond Vision p.102).Coincidentally, Mullarkey's piece is timed with the conclusion of the well-funded weekend symposium on said exhibition (a website with videos, it is promised, will appear). If anyone can locate either, please let me know, as I'd like to see how it went. I'm not holding my breath, but perhaps at least some symposium participants, understanding Mullarkey's critique, saw medieval art not merely as fossils of a pious past, but as catalyst and inspiration for the present.
I'm pleased to recall that the Met made a gesture (however awkwardly) in that direction when they marked Faith & Power (2004) not only with papers, but with prayer.
update: Incidentally, a few of Mullarkey's exquisite collages are on exhibit at Francis Naumann through June 27.