I believe on wobble tests a low score would correlate to a lower body fat percentage, which under conventional standards of Western beauty would be considered to be desirable.
In this case, however, the protagonists appear to be aiming to increase their wobble score, on the absurdly named āWobble-ometerā. This is a subversion of your expectations! Thence: humour.
Itās quite highbrow though, I can see why it wouldnāt land first thing on a Monday morning.