If you've read my Reasoning Rhyme posts, it won't surprise you to learn that this is, in my opinion, utter tosh. Far from being a denial of rhyme, relative rhyme is a more linguistically subtle and complex form of rhyme, a realisation of the potentials inherent in the rhyme system but repressed by half-baked aesthetically conservative statements like Farely's.
Note too the insidious nature of the statement: Farley doesn't actually say we shouldn't use relative rhyme, just implies that twin rhyme* is real rhyme, boys and girls. And who is this "we" anyway? I presume it is the mainstream poetry-writing fraternity, Farley being a self-confessed guardian of the mainstream.
I have nothing against rhyming, whether twin or relative. Yes, I will confess to doing it myself sometimes, but only in the privacy of a poem. Moreover, I like some of Farley's work, even if I dislike anyone positioning themselves as mainstream or bust. However, ill-thought-out statements that creep towards closing down possibilities in poetry rather than opening them up really rile me. Okay, so it was radio and maybe it was off the cuff, but it sounded like something that had been bothering him for a while. Thankfully, he was paired in this discussion with Eleanor Rees, who spoke more sense.
There is always a danger that I might make daft statements like that myself, though obviously not such reactionary ones on rhyme. If I do, betake yourself to your local arms dealer and purchase a small surface-to-air missile with which to shoot me down.
*My terms, not his. See here for an explanation.