I think he does not.
Preferences are not rational or irrational; preferences are the premises you base all your other conclusions on. You need to take these preferences as given.
If anything, you need to recognize that if someone says they don’t want things that bring pleasure, that means that when you said things like “the only reason we think these other goods are valuable is because they produce happiness”, these things are just incorrect. He’s flat out stated something that contradicts one of your supposed truths!
And a closely related issue is blissful ignorance, which I already brought up in another thread. I want certain things about the world to be true. By definition, if you fooled me into thinking they were true, I would experience as much pleasure as they were actually true and I learned that. Yet I don’t think that the two situations are equally desirable, and I would expend some resources to prevent myself from being fooled, even if fooling me will give me pleasure. So I too disagree that the only reason something is valuable because it produces happiness.
You also seem to not have read much of what has been written about these issues. You are not the first person to say “well, I’ll just accept the repugnant conclusion then”, but there are other conclusions that are harder to accept; for instance, see https://plato.stanford.edu/entries/repugnant-conclusion/#AccRepCon
This post combines two drastically different things: human suffering and chickens. I think you are in a bubble if you think they are not only comparable, but so comparable that you can take their similarity as just the natural way everyone is supposed to believe.
To anyone outside the bubble, this is arson, murder, and jaywalking.