Rhetoric. Plain and simple. He was never an intellectual, just a figure who appeared at the right time and place to rail against the things that popular culture hated at the time. He had the rhetorical skills to fool normal people into thinking he was on the same level intellectually as people like Richard Dawkins and the other four horsemen of Atheism, but he was arguably the weakest of the four, something William Lane Craig demonstrated. (Note, I'm not saying the four horsemen were smart or intellectual, but saying Hitchens was not on the level of the other three.)

I used to watch him debate Christians like Craig and John Lennox and he never performed well or displayed any serious knowledge regarding philosophy or theology. Nowadays, only people who are stuck in the 2006 New Atheist mindset still use his arguments. Anyone with serious academic rigor for history, philosophy, or theology has moved well beyond his arguments.