Tell you what, then.  Why not find the first accusation recorded of this alleged practice.  My guess is that it will be from catholic countries that had religious institutions that were threatened by people who did not go along with the institutional orthodoxy of the Roman Catholics.   There are a few thousand years of Jewish religious practice where the accusation has never been made, and the Old Testament is always clear that children are not to be sacrificed.  You might remember that slaughter of children has been rejected since the time of Isaac.