Louis Theroux’s job used to be a lot easier. The British-American documentarian made a career with offbeat TV series, specials, and features that embedded him deep inside various subcultures. On the BBC’s Weird Weekends , which ran from 1998 to 2000, he met porn stars, Las Vegas hypnotists and pickup artists, backwoods survivalists, UFOlogists, and born-again Christian televangelists, who had never heard of him. Affecting a kind of wide-eyed curiosity, bordering on faux-naïveté, he encouraged