No mathematician can effectively model evolution without understanding the underlying mechanics of DNA mutation and all of the forces impacting "random" mutation.
We're still discovering factors that appear to influence the type and location of these mutations so the idea of someone not versed in the field being able to create a predictive model is a non-starter.
Nobody is claiming to be creating a predictive model, they are just making the case that the process being suggested requires time frames many orders of magnitude greater than what we know to be the approximate age of the earth.