Crazy question about the laws regarding dogs for protection?

If you have an attack dog you should have it trained to stand down on command - just like a gun should have a safety catch. If you can't control your dog and call it off then it is dangerous. "Ripping apart anyone who comes in uninvited" often includes harmless people like kids looking for stray baseballs and even extended family members. It's probably down to local ordinances as to whether you'll get a fine or not.