Why Did God Kill Those People?

I hope I'm not beating a dead horse, I've mentioned this several times, but I have to say it again if only because this is a great stumbling block to many people. I'm talking about why did God have Israel exterminate all those people who lived in the land of Canaan? I mean, they were commanded to kill every woman and child, even their livestock in some cases. Why?

I don't know the full answer, and I don't know how statisfying this is for some, but this is the reason that the Lord gives over and over. Manasseh, next king after Hezekiah, is accused of doing "that which was evil in the sight of the Lord, after the abominations of the heathen, whom the Lord cast out before the children of Israel" (2 Kings 21:2). What were these abominations:

"built up again the high places...he reared up alters for Baal, and made a grove" (2 Kings 21:3)--idolatry and the sexual sin that usually accompanied 'groves'

"made his son pass through fire"--the KJV's polite way of saying he sacrificed his own son by burning him to death to false gods

"used enchantments, and dealt with familiar spirits and wizards"--invited influences of false and evil spirits (2 Kings 21:6)

"Manasseh shed innocent blood very much" (2 Kings 21:16)

So, the list is idolatry, sexual sins, human sacrifice of own son, listening to evil spirits, and murder. " and Manasseh seduced them to do more evil than did the nations whom the Lord destroyed before the children of Israel...and hath done wickedly above all that the Amorites did, which were before him" (2 Kings 21:9, 11)

So, two great concerns of most people: 1. Why does God allow evil to happen? 2. Why did God tell Israel to kill all those people? Apparently, there is only so much evil God can handle. The answer to the second question is that He was trying to prevent more evil from happening. And for God, He doesn't see people dying and ceasing to exist, He sees it as moving them to another place where they can't hurt anyone anymore.

I hope to be able to see with God's eyes when the time comes.