Those that wander off end up around our place in the country when the free willy folks release them into the wild.. Strays out here tend to wander off or locals will take them in.
Coyotes certainly target them and the feral cats. Neighbor had a bottle calf long horn killed in the pen yesterday. She came over to ask us if we would shoot on sight which we certainly agreed to. Pit mixed and a Chow roaming the woods around here.
I'm certainly not excusing the OP's officer that was wrong for what he did. He is in a position of authority and responsible to the public. If the dog wasn't a danger the world we live in with social media would have relieved him of the corgi quickly by adoption or getting word to the owners.
When our old Brittney with dementia wandered away several years ago, wife put a word out on FB. It was amazing how many people started driving the roads looking for it. One report two miles away of a dog matching the description a day later. Another day later, we got a phone call from a guy that saw it on his place and penned it up in a shop building before getting online to see if it was lost, two miles away.