The funny thing is, when God told his people to eradicate everyone and everything during war, and not take any spoils, and the people did not follow his directions, this is now why we have such evil demons among us. There was a reason he told his people to eradicate everything. Not leave anything behind. Did the people do it? No. And now we have all these demonically possessed people among us, and we are called to pray for them and forgive them for they know not what they do. That's one of the hardest things that God expects us to do, as believers.