16 “You are not to leave even one person alive in the cities of these nations that the Lord your God is about to give you as an inheritance. 17 You must completely destroy the Hittites, the Amorites, the Canaanites, the Perizzites, the Hivites, and the Jebusites, just as the Lord your God commanded you, 18 so they won’t teach you to do all the detestable things that they do for their gods. If you do what they teach you, you will sin against the Lord your God.”

It's part of their religion. Everything the Israelites are doing, everything the majority of Jews are supporting, is the righteous path according to their fucking books. We who aren't well-versed in the Scriptures would do well to acknowledge this. They are following what should have happened.