Crafting nuanced portrayals of real people is hard, but journalist Robert Kolker makes it look easy. In his two books (“Hidden Valley Road,” “Lost Girls”), he delves into complexities while never taking sides. Here, for the first time on a podcast, Kolker discusses “Who Is the Bad Art Friend?,” his New York Times Magazine piece that became a viral sensation. The story, about a dispute between two writers, raised questions about ethics, ownership, and downright meanness.