I think they make a good point, it's very similar to the concept of modelling infection in a population, but with a twist that tests the methods, so that even a completely new disease can be analysed quickly. Modern disease protocols generally focus on containment and quarantines, but it's not implausible that a disease could be so virulent or deadly as to require a different strategy.
Besides, the vast majority of mathematical papers are not even remotely focused on practical applications. Would you have complained about Newton messing about with calculus?