There was a time when I might have speculated on the cause but then I learned that rather than continuously update my priors I should instead consider every piece of evidence in isolation and adhere strictly to the absolutely non-arbitrary standard of a 95% confidence interval.
The only thing you have to specify is the mass of the Higgs boson, after that, all interactions of the Standard Model are fixed, and you can make predictions to arbitrary accuracy (though it is very hard practically).