God wants the Israelites to kill his creations (God forgets again)

Deuteronomy 7:1 says, “When the LORD thy God shall bring thee into the land whither thou goest to possess it, and hath cast out many nations before thee, the Hittites, and the Girgashites, and the Amorites, and the Canaanites, and the Perizzites, and the Hivites, and the Jebusites, seven nations greater and mightier than thou;

7:2 And when the LORD thy God shall deliver them before thee; thou shalt smite them, and utterly destroy them; thou shalt make no covenant with them, nor show mercy unto them:”  This is the loving merciful god of the bible.  Why would he not save the people he is going to deliver to the Hebrews to kill?  Why would he want anything to be killed?  Didn’t he say in Exodus “20:13 Thou shalt not kill,” or in Deuteronomy 5:17 “Thou shalt not kill.”  What should we believe?