God's a Moral Monster

I'm trying something of an experiment now.  If Christians claim they're going to heaven, I'd like to challenge them how much they really love their God.  It seems a basic tenet of Christianity is that to enter heaven, you must love God above all else.  My question to Christians is simply how they can love God when he condemns tens of billions of good people to burn eternally in hell simply because they sinned once (this not counting the entirety of a lifetime of supposed sins).  If they try to worm their way out of it, I'm going to hold them to it.  I can't believe many people could possibly love something who would burn almost all their relatives, ancestors, and children for all eternity.  If anything, I hope some level of intellectual or emotional discomfort will creep in and unsettle their faith a bit.