I'm the first to post here!
I use to watch these in french, when they showed them on channel 2 in Montreal area. If this is about history, why do they show things like Moses leading his people out of Egypt and the waters of the Nil parted? There was also a part where people pass by Mount Ararat and they see Noah's Ark? Sounds like the makers of these series are confusing myth and history.
And I think you're confusing Once Upon a Time... Man (1978) with Once Upon a Time... The Explorers (1996)
While the first one was about Humanities history, it did present certain theories that would be turned over and out of date only a few years later. It also based the history of the Israelites on the biblical stories. Research into the Moses story is ever ongoing and new developments and theories crop up.
Ok, it could be that I am confusing the 2 shows.
It has been a long time since I have seen the episodes.