Here's a definition of the word defamation, from thefreedictionary:
Any intentional false communication, either written or spoken, that harms
a person's reputation; decreases the respect, regard, or confidence in which a
person is held; or induces disparaging, hostile, or disagreeable opinions or
feelings against a person.
Does this apply to portions of Tom Bissell's Believer magazine essay on the Underground Literary Alliance, reprinted in his collection Magic Hours?