A lesser god would have been OK with entering Canaan and becoming part of the pantheon of the peoples. The LORD was not. He demanded that the Israelites wipe out all the nations of the land. He would not share his glory with any of the demonic entities who claimed ownership of the land and its peoples. They had to be eradicated because the land was holy to the LORD, and the people who lived there had to be holy to him as well. God was passing judgment upon the people of the land because they had sold out to the enemy. He had every right to do so. The LORD of all the earth was taking possession of his land. Those who opposed him had only two choices: flee the land or be destroyed by him.
LORD, purge our hearts of any devotion to lesser gods, and so protect us from your judgment.