From Deuteronomy 20:16 isn’t this what the Jewish people are commanded to do?
https://www.biblegateway.com/passage/?search=Deuteronomy 20%3A16-18&version=NIV
However, in the cities of the nations the Lordyour God is giving you as an inheritance, do not leave alive anything that breathes. 17 Completely destroy[a] them—the Hittites, Amorites, Canaanites, Perizzites, Hivites and Jebusites—as the Lord your God has commanded you.18 Otherwise, they will teach you to follow all the detestable things they do in worshiping their gods, and you will sin against the Lord your God.
Edit: There’s a bunch of really horrible stuff in most of the religious books. That doesn’t mean the people following that religion do it.