I didn’t mean that the mainstream linguists treat speakers like we say that the mainstream economists treat actors, in a confused and psuedo-empirical way. I meant that they treat the natural languages like that. They see the natural languages as the ultimate givens, and go from there, just like the astronomers see the movements of the planets, asteroids, and so on, as the ultimate givens, and go from there.
We can see that attitude in the fact that the mainstream linguists often say something like that no language is better than any other language, and that saying that a part of a language used to be better, or even saying that it used to be worse, is just the idle, confused talk of laymen. They say that it doesn’t make sense to say that our language is better or worse than any other language, or even better or worse than any other possible language, simply because languages are just adjusted to our way of life, nothing more, nothing less. The “primitive” language of a group of hunter-gatherers isn’t any less sophisticated than that of businessmen in a developed country; they are just suited to different purposes; they just developed differently for different ways of living. We in fact might have a tiny fraction of the amount of categories that they do for plants and animals, because we don’t care about it, where they do, because they are hunter-gatherers, where a huge part of their way of life is distinguishing between different plants and animals. Their language is suited to hunter-gathering, and our language is suited to other things. Neither is better; neither is worse. They are just there. We can’t criticize them, just like we can’t say whether the orbit of a planet is “correct” or not. They are just given to us. They are unquestionable, and are the foundation of our science.