You don't know God at all. The bible will show you who is truly is. You think he is cruel, then why didn't he end the world now and billions would go to hell? Why would he let children that don't understand cause they young go to hell? Not even a real person would probably do that (unless they are evil and don't care about children).
I only want to say that all kids go to heaven cause they are too young to understand many thing. Also read the bible and you will notice many things. You don't want to argue against God! The bible is the word of God, so f u want to argue then do it with God to really show if he exists or not(i'm not God).