True, however, even alternate theories besides gradualism - e.g., punctuated equilibrium - generally accept the central theses of natural selection and common ancestry, so I think the author is speaking mostly in terms of those who reject the thing outright, as literalists do. IOW, most non-gradualists take issue with the mechanisms, generally speaking, whereas literalists take issue with the very concept itself, and he is mostly commenting WRT those who reject the whole shebang...
Well, if I may speak for literalists they take issue with common descent. Other than that I think you're pretty much on target as I see it.