That's ridiculous. People really need to learn not to post photos of the dead dogs. Just bury them and forget it. What dog? I didn't see any dog?
Yes, it's foolish to put yourself in the limelight.
I can understand why they do it though.
My experience with people that let their dogs run loose is that when one dog gets killed, they just get another dog who also runs loose. So it continues to be everyone else's problem (especially if you are the person with poultry or sheep. ). I can see why they want to send a message to the OWNER not to keep letting dogs run loose.