I find this thread rather fascinating and couldn’t help but to take another look at Spock’s original statement in “Amok Time”:
You humans have no conception. It strips our minds from us. It brings a madness which rips away our veneer of civilisation. It is the pon farr. The time of mating. There are precedents in nature, Captain. The giant eelbirds of Regulus Five, once each eleven years they must return to the caverns where they hatched. On your Earth, the salmon. They must return to that one stream where they were born, to spawn or die in trying.
I'd hoped I would be spared this, but the ancient drives are too strong. Eventually, they catch up with us, and we are driven by forces we cannot control to return home and take a wife. Or die.
Spock is already on the edge and
he desperately needs to return to Vulcan because
his mate is waiting there. I wouldn’t exclude the possibility that he exaggerated and used analogies to persuade Kirk to get him there. After all, he did return - but he didn’t take a wife and he didn’t die!
Since he talks about “ancient drives” I’d presume this would also include the Romulans because they and the Vulcans haven’t be separated for more than just 5,000 years. But the Romulan civilization didn’t die 4,993 years ago because they couldn’t return to Vulcan.
The more I think about it, the Pon Farr looks like a result of their own self-imposed behavioural practices, where it becomes impossible to ignore the Vulcan sex drive for any period extending seven years. Hardly the thing Vulcans want to go public about, thus it’s covered up like an ancient biological thing outside of their individual control.
Looks like Spock hints that in "Amok Time":
KIRK: I guess the rest of us assume that it's done quite logically.
SPOCK: No. No. It is not. We shield it with ritual and customs shrouded in antiquity.
Of course, ST III:TSFS still suggests otherwise but I wonder which rationalization makes the most sense in the big picture.
Alternately, we could always pretend that there was more going on between Spock and Chapel in "Amok Time":
CHAPEL: Yes, Mister Spock?
SPOCK: I had a most startling dream. You were trying to tell me something, but I couldn't hear you. It would be illogical for us to protest against our natures. Don't you think?
Bob