For God to prove himself on demand, physically, would be a grave disappointment, and the strongest Christians should be considerably grateful that he chooses not to do so. The skeptic endlessly demands proof, yet God refuses to insult the true intelligence of man, the '6th sense', the chief quality, the acumen which distinguishes man from the rest of creation, faith.
Of all the major religions, or lack thereof, the atheist's is one of the best pretenders: his foundation for all existences, as well as moral behaviors for the permanent good of mankind, begins at science but ends at himself, the Napoleon complex of both intelligence and imagination. On the other hand the anti-theist wouldn't survive without a deity beyond himself to hunt. He doesn't pretend, he simply nullifies his own position.
As Peter Berger has noted, the strategy of apologizing for Christian faith by trying to demonstrate its social utility is always eventually self-liquidating. Sooner of later people realize that a great many of the supposedly practical and secular benefits of the Christian religion can be had more easily without religion.. The logic of practical atheism may well be more deeply ingrained in the evangelical tradition than conservatives perhaps have realized.
The typical atheist rebels against God as a teenager rebels against his parents. When his own desires or standards are not fulfilled in the way that he sees fit, he, in revolt, storms out of the house in denial of the Word of God and in scrutiny of a great deal of those who stand by the Word of God. The epithet 'Heavenly Father' is a grand reflection, a relation to that of human nature.
So whom does God wrong in commanding the destruction of the Canaanites? Not the Canaanite adults, for they were corrupt and deserving of judgment. Not the children, for they inherit eternal life. So who is wronged? Ironically, I think the most difficult part of this whole debate is the apparent wrong done to the Israeli soldiers themselves. Can you imagine what it would be like to have to break into some house and kill a terrified woman and her children? The brutalising effect on these Israeli soldiers is disturbing.
To be honest, one can only feel glad that so many modern iconoclasts consider Christianity to be full of exceptionally hypocritical, religious zealots - it's biblically accurate and a prophecy fulfilled. The old smoke screen is one of Satan's favorite tricks. He conceals the authentic. He has a persistent strategy of targeting those who remind him of Christianity because he fears those who remind him of Christ.