In a way, I suppose, it makes sense that a cartoonist as image-conscious as Benjamin Marra would find “inspiration” in the ultimate story of excess and artifice, American Psycho, but for a guy who’s spent most of his career deliberately confounding readers as to how much of what he’s doing is sincere and how much is, as the Brits would say, a “piss-take,” his decision to do a bunch of pencil-and-ink drawings based not on Brett Easton Ellis’ novel but, specifically, on the Mary Harron cinematic adaptation starring Christian Bale is, if anything, too obvious — after all, when you strip away any pretense of “spoof” from Marra’s work, you rob it of a pretty good chunk of whatever ostensible “power” it may possess. “I just dig this shit” is an honest enough statement to make, however surreptitiously, but when you steadfastly refuse to answer the natural follow-up question…