Who are the Mandaens? They are an ancient Gnostic sect, (probably the last Gnostic sect remaining). They revere John the Baptist, but they don’t think much of Jesus. (Or Christians, Jews, or Muslims for that matter.) Their most important religious rite is baptism (no surprise there). They managed to survive to this day, mostly along the Iran/Iraq border, by trying to stay under the radar. But after the US invasion of Iraq they were severely persecuted, and most of them fled to Worcester, Massachusetts. There is more I could say, but I’ll keep it short and sweet.
Anyway, could the existence of this group be why the Gospel of John makes such a big deal about John the Baptist being not the light, inferior to Jesus, and so forth?