Lovely, as always. (Although this whole thing is not really a "contretemps," but rather a letter to the editor taking exception to something everyone else has forgotten about.)
Lethem complains that Wood "is a high priest, handing down sacred mysteries. To one who pines for a borderless literary universe, he looks like a border cop, checking IDs." But that's what thrills Lethem about being reviewed by Wood. It may be that Lethem wants to have it both ways: to assert a universal, democratic, Quakerish, anti-hierarchical literature, in which Spiderman is on an equal plane of literary legitimacy as Raskolnikov; but also to feel rewarded by admission to a hierarchy of cultural importance, in which being reviewed by James Wood is legitimizing--and sanctifying--in ways that being reviewed by James Schmuck is not.
I also wonder if Lethem is bugged because sometimes Wood seems to be saying that, while Wood is moved by things the author writes, he is unmoved at those times by things the protagonist experiences. We should all be so imperfect, but I can see how that might rankle--as they used to say about football games that end in a tie, it's "like kissing your sister."
In any case, this kind of thing never turns out well. Lethem's essay is exactly the kind of letter-to-a-spurning-lover one should always write, but never send. Wood is one of the only critics alive who will quote an author's sentences, and then dissect them, by way of discussing style. A more attentive reading than that, you don't get.