The New York Times treats him as an expert: "Eliezer Yudkowsky, a decision theorist and an author of a forthcoming book". He's an Internet rando who has yammered about decision theory, not an actual theorist! He wrote fanfic that claimed to teach rational thinking while getting high-school biology wrong. His attempt to propose a new decision theory was, last I checked, never published in a peer-reviewed journal, and in trying to check again I discovered that it's so obscure it was deleted from Wikipedia.
Lol, I'm a decision theorist because I had to decide whether I should take a shit or shave first today. I am also an author of a forthcoming book because, get this, you're not gonna believe, here's something Big Book doesn't want you to know:
literally anyone can write a book. They don't even check if you're smart. I know, shocking.
Plus "forthcoming" can mean anything, Winds of Winter has also been a "forthcoming" book for quite a while