Years ago I had neighbors with a chow that got loose several times and attacked multiple dogs and one person. I knew the couple and they were intelligent, reasonable people so I never understood their blind spot in allowing that dog to live.
People get really weird when it comes to their dogs. About 2 years ago we had a dog that was aggressive and had to be watched carefully. One evening our nephew comes over to visit my sons. He is used to just walking into the house. I'm off somewhere else in the house. Dog lunges at him and nails him in the hand. It's later in the evening and no urgent cares are open. Off to the ER, 4 stitches and 3K later in medical ER bills. The wife and I decided it was time to put him down. This dog came from the Humane Society, which I totally support. From now on we get dogs from professional rescue organizations. They seem to do a great job of vetting the dogs. Are they good with young kids, how are they with other dogs, cats in the house. We got our current dog from Giant Paw Prints out of Valpo. Could be luck but she is the best dog we have ever owned.