That was pretty much the year movies became that big; Griffith’s Birth of a Nation, released the previous year, more or less revolutionized the filmmaking process and near-singlehandedly codified long-form cinema as we know it today. Of course it also made the KKK the good guys, so, you know, some aspects coulda been better.
It would be very out-of-character for him to just now try to distance himself from the morally reprehensible, so I’m going to assume he simply forgot the man existed the moment he left his field of view.