I honestly cannot guess who shot a buggy horse. Why do young poeple do stupid and hurtful things — youtube.com is filled with videos to prove that fact.
I do know that such horses are, in general, American Saddlebred horses or descendents of Virginia Saddlers. These are exceptional horses; people oriented and with incredibly comfortable gaits as riding horses. The Amish use them as buggy horses because they are easily trained and can maintain forward motion. Most of the Confederate Army’s officers during the War Between The States were mounted on American Saddlebred horses.