"However, in the cities of the nations the Lord your God is giving you as an inheritance, do not leave alive anything that breathes. Completely destroy them — the Hittites, Amorites, Canaanites, Perizzites, Hivites and Jebusites — as the Lord your God has commanded you."
That's a quote of something God said several thousand years ago. It's not urging people today to go out and slay Hittites. Assuming you could find any Hittites.