Quentin Tarantino’s Once Upon a Time . . . in Hollywood is steeped in an element critics love: It celebrates movies, thus validating the lives of those who spend inordinate amounts of time watching them. So many critics love this aspect of Tarantino’s latest that they missed an equally important factor: It mercilessly sends up leftist values. In its foundations, it’s so breathtakingly right-wing it could have been made by Mel Gibson.