Since the source of the quote in the OP is currently suspended for trolling, we probably shouldn’t take anything said completely seriously.
Still, he peels scabs off old wounds. The elitest detestation and mockery of genre fiction goes way back. Nothing brought high dudgeon to the literary establishment in the 19th century faster than the hundreds of millions of dime novels sold, followed by the rise of the pulp magazines. Science fiction especially was despised as fodder for illiterates, made worse because it appears to be a prose version of lurid Sunday comic strips, which were aimed at both kids and adults but considered fit only for kids to grow out of. When Edmund Wilson published his essay, “Who Cares Who Killed Roger Ackroyd?” in 1945, it went viral. A look at the first paragraph, though, provides insight.
For years I have been hearing about detective stories. Almost everybody I know seems to read them, and they have long conversations about them in which I am unable to take part. I am always being reminded that the most serious public figures of our time, from Woodrow Wilson to W. B. Yeats, have been addicts of this form of fiction. Now, except for a few stories by Chesterton, for which I did not much care, I have not read any detective stories since one of the earliest, if not the earliest, of the imitators of Sherlock Holmes—a writer named Jacques Futrelle, now dead, who invented a character called the Thinking Machine and published his first volume of stories about him in 1907. Enchanted though I had been with Sherlock Holmes, I got bored with the Thinking Machine and dropped him, beginning to feel, at the age of twelve, that I was outgrowing that form of literature.
To sum the actual article. Prominent adults love stuff that he’s never read. He reads a handful of books and doesn’t fall instantly in love. Therefore it’s a dead end.
Genre is mostly for entertainment. Literature is mostly for higher values. That’s mostly true, and says nothing. Is entertainment strictly for kids and childish adults? What are these higher values and who gets to say that they’re higher? In today’s literary world, genre tropes and techniques abound. In today’s genre world, nuanced examinations of morality, identity, and society can easily be found. The extremes at either end are identifiably different, yet the gooey center doesn’t provide simple markers. (That’s why literary novels have “A Novel” on the cover for the elites who don’t want any of that icky genre stuff on their bedside tables.)
Everything else is money. Genre outsells literature by orders of magnitude. Of course the literary establishment hates that. Steve Hely wrote a bitter satire on the issue, How I Became a Famous Novelist. I hate to recommend it fully, because the protagonist starts as an asshole and gets worse the more famous he becomes, but the parodies of bestseller fiction are worth turning pages for. Those aren’t for children, yet no self-respecting adult would want to claim them.
Bestsellers are a separate genre, a middle ground of hackery populated by only a handful of the super-successful, yet considered to be the norm. That’s why this silly argument keeps raising its head.