The author is speaking specifically about the fae, but I think it applies well to other non-human beings. Especially the cultural approach she suggests at the end.
In and of itself its fine to have beliefs from odd sources – entire religions are founded on fiction and there’s nothing wrong with deciding to go with a belief you gleaned from a novel – it only becomes a problem when its put forward as genuinely older folk belief and becomes mainstream. Because when that happens, when it becomes popular under the guise of genuine traditional folklore, it actively erases the older cultural folklore which in many places is already struggling.
When a dominant culture starts to rewrite minority folklore not from a place of belief but for entertainment, even if those rewritten ideas are then absorbed again as beliefs, it’s a big problem. Not only because it accelerates the decline of the original culture but also because it raises the question of how much depth these new beliefs actually have to them....
People often question why any of this matters, why we should care whether a belief is genuinely folkloric or pulled from modern fiction or invention. There is of course a fluidity to folklore that means today’s urban legend is tomorrow’s folk belief and sometimes today’s fiction becomes the folk belief of the next century. This is a particularly touchy question in modern paganism where people are often looking for any and all sources on a subject like fairies. But I think Nimue Brown sums it well in a recent blog, saying that there is a difference between being part of a culture and its evolution and being outside of it and taking material from it to use outside its context. Too often what’s being taken as belief from modern fiction is the latter, material that is disconnected from actual cultural belief and born simply as a plot device.
If you are seeking to incorporate belief in fairies into your spirituality, to approach belief in them the way the modern living cultures that believe in them do, I suggest treating them as you would a foreign human culture you are interested in learning about. And I would sincerely hope, to forward that analogy, if you want to learn about Ireland you would look to solid non-fiction sources and accounts written by people with first hand experience, rather than fiction. In the same way with fairies while fiction can be fun and entertaining we need to be careful not to blur that line and start seeing it as depicting actual folklore, because most of the time it isn’t.