More ridiculous than asking CS questions of a front end dev. I'm a self-taught front-end dev who has flunked numerous interviews because of a lack of CS degree and being able to get through the sorting algorithm questions. I then went home and have spent lots and lots of time teaching myself those fundamentals, if only to interview better. Those fundamentals have made me a vastly better front end dev, able to efficiently solve problems I wouldn't have been able to solve a year ago.
I have had the exact same experience with the author of the article regarding a total absence of actual front-end related questions, though. Not sure how to feel about not getting those gigs.