Doesn’t this depend on whether one is referring to fluid intelligence or crystal intelligence? Human babies may have the same crystal intelligence as adult pigs, but they have much higher fluid intelligence.
I think what happened here is that the vegetarian failed to realize that the component of intelligence that people find morally significant is fluid, not crystal, and then he equivocated between the two. EY realized what was going on, even if subconsciously, which is why he trolled the vegetarian instead of disputing his premise. Finally, Fallible failed to pick up on the distinction entirely by assuming that “intelligence” always refers to fluid intelligence.
It’s useful until the jester gains a reputation as someone whose views shouldn’t be taken seriously, at which point the jester’s dissent may begin to have the opposite effect.