We have free will, and the atrocities you mention are acts of men. Why would you blame God for them?
But your counter argument is just setting up for more of that "mysterious ways" babble that the clergy have been using for centuries to keep the plebs coming to church. And pay their tithes.
So, if you ask me: what does it take to accept that a particular deity is real: at least do an open, clear, undeniable miracle, not weakly undo something you've set up yourself and have let fester for too long.