The idea that the population growth in the hills was people fleeing the cities for a more egalitarian life has been advocated, but it sounds more Marxist than realistic. People chased down escaped slaves over longer distances. It was a rather large number of people with notable cultural differences. While not free of idols, the new population seemed to have a lot less of them than typical for the region. The frequency of idolatry was rather up and down in Israel’s history.
“You know about the 40 year Piltdown man” hoax that secularists fell for"
This involves two fundamental errors besides what has already been discussed:
“Secularists” perpetuates the lie that young-earth or anti-evolution is THE religious position and anyone accepting evolution is “secular.” de Chardin is an obvious counterexample as someone who was clearly non-secular and who was influenced by Piltdown in his ideas about human evolution.
Second, it is a double standard. It faults scientists for being fooled by an elaborate hoax, which they rejected as soon as the evidence became available, while ignoring the fact that young-earth advocates are still repeating false claims that have been repeatedly debunked for far more than 40 years. Repeatedly bringing up Piltdown in such a context by the professional young-earthers is a dishonest ploy aimed at creating mistrust of legitimate science rather than an honest example of fallibility. Carl Baugh is still promoting fake footprints and dinosaur footprints as human. The moon dust lie hasn’t disappeared. Most young-earth arguments are worse than believing that Piltdown Man was real because the evidence was clearly against the young-earth claim from the beginning.
Of course, many bad claims against the reliability of the Bible have equally long histories of being known to be incorrect.