It may not make sense but it was so cool and exotic.
And basically a great effort to make some of the aliens in Star Trek act differently from humans.
I have another pon farr type question though. Sorry to change the topic slightly. The 'Intrepid' had I assume 400+ Vulcans aboard. Assuming everyone on board goes into pon farr every 7 years then they'd be turning back to Vulcan 400/7 ~ 57 or times per year or about once a week. Is my maths OK? Or was there something in DS9 or VOY about Vulcans always serving in Starfleet as couples. Except for Spock or Tuvok or that other Vulcan guy in VOY.
Maybe living in an enclosed ship, their pheromones cause their cycles to synchronize.