If the word 'rape' is translating at all correctly, Keltham is having some trouble seeing how the notion of a 'rape fetish' isn't as obviously paradoxical as 'asking somebody to rape you'; but presumably there's some elided meta/object distinction that makes sense of it, and in any case that's not the most urgent topic right now.
So. Pilar has the fetish. But it's very common locally, maybe it's 1/3 of the population, say, if he'd also checked Ione then taking the universe at face value there'd be a 55% probability of at least one of the two having the fetish; but still, it should probably be called something like one bit of evidence favoring the eroLARP hypothesis.
"I wasn't saying Sevar was too stupid for it," Keltham replies after taking a moment to think. "I was saying the concept structure came at the end of a long series of other concepts, that would take too long to explain. Higher Intelligence doesn't let you bypass that sequence, what would be needed is that you have a lot of prerequisites that I'd guess to be outright unknown in Golarion."
There's also the concern about whether explaining the notion of an eroLARP to people inside the eroLARP will drive them insane or cause this universe to collapse. But if Carissa is able to hear him talking about his weird theories and the very smart people immediately investigate them in Pilar, it doesn't seem like that kind of eroLARP anyways.