It is hard to paint anything but a grisly face on this remorseless serial killer. There’s just nothing good to say about a homosexual psychopath who lured victims to his apartment and implacably snuffed them out. But if some obscure Home & Garden channel can overlook the unsavory backstory, there’s a doc here, a program that could catapult a seldom-watched network into cable prime time: What We Can Learn About Refrigeration From Jeffrey Dahmer.