It is still rare.
Check on your own communities. Go with a certain radius and a number of years. Research how many dogs have been killed by police in incidents like the previous three incidents.
I am sorry, I am not going to make a dog live in a crate whenever I am not right there, because 3 dogs out of 3 million dogs got shot while at home by a cop this year. We had an almost identical situation, thought the dog was chained in the front yard. Wrong address, cop shot the dog, then tried to cover it up, by cutting the chain -- witnesses. The cop was fired. That was years ago and about 30 miles away from me. I have not heard of ANY other cop-killed-my-dog-while-he-was-innocently-protecting-his-home here in over 30 years of living out here.
Cops, for the most part LIKE dogs.
When I was a teenager, I roamed a lot, and sometimes I had my mutt with me. She wasn't leashed, we were just bumming, she and I. She would steal cat food off of people's porches and would wait for me to get a chocolate donut from the 24 hour Lawson's to give her. (She lived to be 14+ before we put her down, inspite of Dad's and Purina dog food, chocolate donuts, and occasional stolen cat food.)
But anyway, a cop was driving through a parking lot, and I called to him, "Don't hit my dog!" And he was affronted, he said he wouldn't hit my dog.
My brother left his chow mix in his basement while he was on vacation, and I went over to feed it. Well he had a stack of mattresses down there, and the dog climbed up them and chewed through the window and was attacking (I don't think it actually bit her though) the high school principle's wife. The cops called my mom (small town, she was the clerk of the village at the time) and she told them to shoot the dog. He said he couldn't shoot the dog.
Cops really don't want to go around shooting dogs. Yes, there is the odd scumbag that might hate dogs, but he is in the minority. I bet this officer is getting a lot of guff from other officers for shooting that dog. And adding insult to injury that it was the wrong address.
No one has to sneak onto a property for a stolen ladder. They do not have to kill someone's dog for a stolen ladder. This guy is probably in trouble.
Maybe large departments have good systems for training cops, but here you can be 18 and work as an auxiliary officer with very little training, and yes, you do carry a gun. Scary. That may have changed since 20 some years ago when I was seventeen and working in my store at 2AM and the auxiliary snuck in and crept up on us. I told him he scared the bleep out of me, and he said I was lucky he didn't enter with his gun drawn.
Later that night he saw me riding my bike and asked me about my sister who was with me at the shop. I asked him if he was married and he told me he was only 18. I was thinking, OMG, they let you carry a gun??? But, they did then. And I am sure that dealing with people's pets was probably not something they dwelled upon with these part-time, sub-rookies. Leaving them to work the night shift here on their own though, that probably could go way bad. Most of the guys I see at night are regular officers now.
I am sorry this dog died. It was no fault of the owner. I don't know what should happen. They are investigating this, and my guess is that the officer will lose his job. My guess is that police work requires people use decent judgment. I am guessing within the first year, an officer's judgment is scrutinized and departments probably take the opportunity to prune the ranks of those who show problems in this area. Poor judgment can get him killed, and can get others killed.