Why did God wage war against the Canaanites?
I agree with hamilcarr that the Society's record of scholarship is dismal. As Leo points out, Israelite and Canaanite cultures overlap; in fact, Mark Smith, in The Early History of God, notes that Israelite culture was largely Canaanite in nature, as is particularly evident from looking at artifacts from the early Iron period. The rise of Israelite Yahwistic monolatry was more a case of them breaking with their own (Canaanite) history rather than the kind of divine innovation that a literal reading of the OT might indicate.
But in the JW world, any kind of real live reputable scholarly research, NOT taken out of context, is unwelcome and "worldly thinking"--no, worse--"worldly philosophies."