Well, I guess something had to replace sci-fi as the ghetto genre. lol
But more seriously, this is an extremely myopic view of the entire field. To him, it starts with Frankenstein ( which I thought science fiction had already claimed ) and ends with House of Leaves. There's a lot of in between he missed. No mention of Clive Barker? The jibe at Stephen King, he's a juggernaut that can't finish his stories properly. Edgar Allen Poe seems to be missing from the earlier authors.
Hopefully someone takes him to task, it'd be an interesting dialogue.
Also, hasn't the genre fragmented anyway-- dark fantasy, urban fantasy, etc ... I'm sure if we looked we could find the mainstream authors with works with element of horror