. . . a monk, whan he is recchelees,
Is likned til a fissh that is waterlees,
That is to seyn, a monk out of his cloystre
But thilk text heeld he nat worth an oystre.
And I seyde his opinioun was good.
Bowers notes that Tolkien found fault with these lines, and ascribes it to Tolkien's faith rather than his scholarship:
As a devout Catholic, Tolkien responded to the portrait's worst
anti-monasticism by rejecting a particularly unflattering passage
as spurious: 'we can scarcely accept [lines 180-184], as they
stand in our text, as Chaucer unadulterated.' Editors sometimes
rationalize censoring their texts by claiming anything they
dislike could not have been by their author. Skeat raised
no doubt about the authenticity of the lines that Tolkien
questioned, nor does the current Riverside Chaucer.
(Bowers 178, emphasis mine)
Certainly Tolkien very much subscribed to the old or 'heroic' school of medieval manuscript editing, wherein modern-day scholars had great confidence that they understood Old and Middle English texts better than did the scribes who were actual speakers of those languages. And Tolkien's subsequent work on Chaucer ('Chaucer as Philologist: The Reeve's Tale') is posited on the idea that the manuscripts of Chaucer's works represent corrupt texts in need of editorial correction. What is remarkable is that Bowers ascribes Tolkien's dissatisfaction with the lines in question directly to their Xian content. So we have Tolkien's statement, without explanation, linked with Bowers' statement, again without explanation.
Reading Bowers' discussion of Tolkien's stance on editing makes me want to dig out my old essay on Tolkien as an editor of medieval texts, given at Kalamazoo a few years back but set aside when still only about two-thirds written down when other projects crowded in and interfered with its completion. Worlds enough and time.