That might have been his coverstory had it not been for this scan from The Making of Star Wars by JW Rinzler here: https://otnesse.tumblr.com/post/162081709399/this-is-from-george-lucas-1973-notes-for-star
He makes it very clear in these first draft notes, dated 1973 (can’t stress this hard enough), that the Rebels were VC members and the Empire was supposed to be America “10 years from now.” And actually, Hollywood DOES love movies that are against Nazis, because they project Conservatives onto the latter. For goodness sakes, Apocalypse Now actually had Ride of the Valkyries playing on the chopper’s speakers in order to subtly connect the American forces with Nazis. Cowboy movies? Yes, they definitely hated them during the 1970s, but not anti-Nazi stuff, they love it especially if they can implicitly connect Conservatives to them.
Not to mention he constantly bragged about it after the fact, as late as this past May in fact on James Cameron’s AMC series, when he really had nothing else to lose by that point anyways (being out of a job in Hollywood and having sold his creation to Disney).