I figured you had him slip a little to let us realize that he was from the future, but if he's really about stamping out anachronism it becomes less believable that he would slip *a lot.*

Or you could propose that the song takes place uptime, "at home" so the anachronisms aren't a problem. In that case a rewrite to direct the character's hostility toward "things that distort future understanding of history" away from perfectly period things like priests and idols and untested ideas would fix any remaining confusion.