I think that the idea of cultural appropriation CAN be an issue in criticism. It can generate some insights, such as those the author expressed in his example of the various types of forest gods in literature, poetry, art, etc. However, what could be a valid CRITICISM of a work of art isn't really what's being encouraged: what's being encouraged is a blacklisting of various works and their creators when they are deemed to have committed cultural appropriation. In other words, they are not saying "I see an appropriation of an idea that can only be expressed by people with such-and-such an experience/background/etc." They are saying "I see an appropriation of an idea that can only be expressed by people with such-and-such an experience/background/etc. Therefore, No One should be allowed to see/read/hear it." That's what should be debated here: not the criticism (people are free to criticize all they want) but the application of it through censorship.