The answer to the topic question is, any creature that belongs in my fenced backyard (it can be my own dog, my cats, my chickens, my child ) is more important than any rabid beast coming from outside. It doesn't matter if it's a 25K$ dog. Maybe the owner should have spent 10 extra bucks for a leash and nothing bad would have ever happened. I spent money for a fence to keep things outside, and a fence is already a clear warning that nothing and nobody is welcome inside without permission.
I witnessed a random dog, who was let free inside my neighbor unfenced property, chasing and almost killing my neighbor cat, almost jumping my fence to get to the cat. The owner watched, pleased. I confronted the lady and told her that if I ever saw that dog without a leash inside a private property again, I would have shot it on sight.