RE: what I would like to know.
"is
"All in all, researchers found 17 previously undiscovered religious monuments"
How do they know that?
They were just as likely to have been pagan cannibals for all we know."
From the point of view of those who built these complexes, yes, these are religious monuments - the pagans are the ones who are doing the modern research on the remains.
I recall reading a book some years ago that mentioned rituals associated with the dead and visiting the bones on feast days (who wants to skip school today and go on a picnic with great-grandad?) - the author suggested that Stonehenge and similar monuments were basically charnel houses.