Katha Pollitt, a colleague of his at the Nation, says what I would have suspected:
So many people have praised Christopher so effusively, I want to complicate the picture even at the risk of seeming churlish. His drinking was not something to admire, and it was not a charming foible. Maybe sometimes it made him warm and expansive, but I never saw that side of it. What I saw was that drinking made him angry and combative and bullying, often toward people who were way out of his league—elderly guests on the Nation cruise, interns (especially female interns). Drinking didn’t make him a better writer either—that’s another myth. Christopher was such a practiced hand, with a style that was so patented, so integrally an expression of his personality, he was so sure he was right about whatever the subject, he could meet his deadlines even when he was totally sozzled. But those passages of pointless linguistic pirouetting? The arguments that don’t track if you look beneath the bravura phrasing? Forgive the cliché: that was the booze talking. And so, I’m betting, were the cruder manifestations of his famously pugilistic nature: as F Scott Fitzgerald said of his own alcoholism: “When drunk I make them all pay and pay and pay.”No shortcuts to good writing on the booze track. I am (somewhat famously among my friends) terrible at holding my liquor; I've never been able to take even a small, mass-adjusted fraction of what some others I know can put away. But I wonder if in the long run that will turn out for the best.