If you have control over your dogs I have no problem with whatever breed someone wants to keep. If this was a golden retriever it would get the same treatment. I've had a dog or 2 with me all my life. Big dogs. But I always say the worst thing that can happen to your dog is someone being afraid of it. A guy moved in near me not to long ago with one of those American bull dogs. Big scary bitch. First time I saw that dog it stood up and looked at me from about 15 ft away. Guy came around the corner and told that dog "down" dog laid right down. I never gave that dog another thought. Not concerned about it one bit. Not worried about my kids ,my wife , nothing. This isn't about pits for me, it's about my yard and my family. I'm starting to think I'm gonna have to kill it, but I hope not.
If you must kill that dog you have no one to blame but its master. I really hope it doesn't come to that, but you'll do what you need to do for your family.