It would probably be more rational to show just who the Canaanites were and what they were doing. They were way worse than Sodom and Gomorrah
I think what troubles a lot of People is God using His people — THE ISRAELITES to do the dirty job of killing men, women and children.
If you were to ask me to do it, I wouldn’t have the heart to actually act ( of course, this will get me into trouble with the Almighty).
Not sure if it would have been more acceptable to men like Dawkins had God simply destroyed the Canaanites the same way He did with Sodom and Gomorah instead of commanding His people to do the killing.