The distinction drawn here is linguistic descriptivism vs. prescriptivism. If we take "actual linguist" in this context to mean scientific-minded academic researchers, the field largely requires itself by nature to be descriptive--they're attempting to document and describe actual human behavior "in the wild". It is, typically, not the business of scientists to be dictating terms to reality (they leave that to the engineers). As Emily points out, L'Académie française doesn't seem to contain a single academic linguist.

I suspect this is mostly a disagreement on the definition of "linguist".

Some academic linguists further take an active stand against prescriptivism, even outside the context of their field. Language Log has of course discussed the issue, such as some recent posts here and here, which you've probably already read, given that you linked to Language Log in the main post.

The French Academy is looked down on as being conservative almost to the point of absurdity by just about every linguist I've read on the topic.

ETA: I just skimmed through the Wikipedia article on the topic, which gives this:

although most academicians are writers, one need not be a member of the literary profession to become a member. The Académie has included numerous politicians, lawyers, scientists, historians, philosophers, and senior Roman Catholic clergymen.

Not a linguist mentioned.