The column uses the most stupid and histrionic way it can to express an otherwise sensible point: Lots of shitty authors rely on overblown and grotesque descriptions to shock an audience that is neither shocked nor impressed by such stuff.
Also, he, and most of the reviewers he quotes, misuse the word "nihilistic".
He's over-generalising from a few cherry-picked examples though. Martin's more well known than any of the stuff he mentions, and his Song of Ice and Fire includes plenty of rough, grim stuff in it, but it's neither nihilistic nor badly-written.