Truly, it boggles the mind.
an update for anyone who cares: the website is just as broken over a year later. The offerings for fitness class packages no longer overlap with the matching type of cruise; on a 8+ day cruise you are allowed to book the 4 or less option, the 5-7 is present but unusable, and the 8+ option is absent. Booking the only one I can and crossing my fingers...