Patrick Frater Asia Bureau Chief Rithy Panh, director of “Rice People” and “S21 The Khmer Rouge Killing Machine” is an icon of art-house cinema, at once political, unique, and charming. The iconic image may be another of his confections – a palatable work built on uncomfortable facts. On the incomplete evidence of a 50-minute on-stage dialog at the Busan International Film Festival on Sunday, Panh comes across as simultaneously contrarian and principled. A curmudgeonly veteran and yet a filmmaker still curious to learn. “If there were no Khmer Rouge maybe I would not be a filmmaker,” he said of the Communist insurgents, who won the Cambodian civil war in 1975 and whose brutality and atrocities he has spent a lifetime documenting and exposing.