Why is the Boston Terrier under the non-sporting dog group and not under the Terrier group of dogs?

I was wondering why the Boston Terrier is placed under the non-sporting dog group when its name suggests that it is a terrier. How did this come to be? What is the history behind this dog breed?

Because the Boston Terrier was bred as a companion and was never bred to do the work of a terrier.

Boston Terriers do not have any functional terrier ancestry, they were bred from several varieties of English and Continental Bulldogs and toy Bulldogs. They were never used as ratters or to flush game gone to ground and so they can't be classified as a "terrier" (from Latine "terra" meaning earth). They belong in the non-sporting group due to their function as an all-around companion dog that was never used for the functions described in the other groups: not a bird dog, not a hound, not a herding dog, not a working dog, not small enough to be a toy dog, never functioned as a terrier. The non-sporting group is the "catch-all" for dogs like that. The Tibetan Terrier is another dog mistaken called a terrier that is in the non-sporting group.

Boston Terrier originated from the United States of America. The original Boston Terriers were a cross between the English Bulldog and now extinct English White Terrier. The Boston Terrier breed was developed in the stables of Boston, Massachusetts, as a fighting dog. The breed has been around since the year 1870. A man named Robert C. Hooper bought a dog named ‘Hooper’s Judge’, a cross between an English Bulldog and an English White Terrier. Over time, the breed was bred down in size. In 1889, about thirty people from the Boston area organized the American Bull Terrier Club. They bred dogs known as "Round Heads" or "Bull Terriers". Bull Terrier breeders objected that these crosses were not Terriers. Bulldog breeders also objected because they were not Bulldogs. In 1891 the name was changed to the Boston Terrier Club of America, (BTCA), taking the name where they originated. In 1893, the breed was accepted by the American Kennel Club.