I think you are misinterpreting the quote. He meant that experts (computational linguists and statisticians) had a firmer grasp of the task of inference in language than linguists, who tend to care more about formal structure (i.e. Chomsky's competence/performance distinction) and are less aware of problems like overfitting. If anything, it's stressing the importance of domain expertise, just suggesting that who those experts are may be nonobvious.