I haven't heard the recording in question, though I do like a lot of "late" Coltrane, but it's certainly possible for it to be simultaneously true that (A) the recording is "not great" (or even "not good"!) and (B) Dyer pooped out a turd.
Also - and I can't believe I didn't make this point pre-edit - there is a WHOLE OTHER THREAD DEDICATED TO THIS RECORDING in which people say positive stuff about it, whereas this thread is dedicated to Dyer's review. Ergo your observation.
The vituperation is because Dyer used this one recording to build a IMO specious case that late Coltrane as a whole, and Free Jazz in general, had by 1966 more or less proved itself to be a musical train wreck.
From Dyer's piece:
"Or perhaps it [the Temple recording] just makes evident what was harder to grasp in the intoxicating frenzy of the moment: that free jazz had run its course—come up against its limits—while the course was still being run and the limits breached. The fact that things fall apart does not mean that they can’t keep going, especially given the huge freight of history that the music and its revolutionary promptings and trappings is, at this point, obliged to bear. On that note, one wonders about Yeats’s claim that the best lack all conviction while the worst are full of passionate intensity. Trane is as passionately intense as ever. Did he lack conviction? Maybe the Yeatsian opposition is false and passionate intensity covers up or disguises a deeper lack of conviction."
That's not dismissive, bordering on disdainful? "The fact that things fall apart..."? In 1966? Hello, Art Ensemble, for one of many.
A dangerous thing to do, making such sweeping generalizations for the "general public" (who just might pick up that very statement as a "fact" to be repeated elsewhere in a most inappropriate way), and I can understand that this is galling to those who believe in the music and know the finer details of it.
I think that all of the above answer David's posts very cogently.