It can be challenging today to find accurate information on the history of the pit bull because the information has become very convoluted. But a dog bred for baiting tells you something about the breed, as it is difficult if not impossible to completely eliminate instinctive characteristics from a breed of dog. (For those who don't know, baiting means that another dog was either chained or thrown into a pit where the most ferociously-bred dog would attack and kill it. This was outlawed in many countries but the practice continued with fervor, and still continues illegally to this day, including here in the U.S.) They were also used legally by butchers to grab onto a bull's nose and not let go so the bull could be overcome and slaughtered, which was too difficult and dangerous a job for humans. There's little question they were bred to be aggressive toward other animals and were primarily used for blood sports.
I think the ASPCA here does a decent job of summing up in their position statement on pit bulls.
https://www.aspca.org/about-us/aspca-policy-and-position-statements/position-statement-pit-bulls
And it seems to coincide with what you are saying:
(Although I would feel much better about your DS's dog if he had not had a shock collar used on him, if I'm being truthful.)
As for the military, the pit bull was not, and is not, a dog used all that much. Stubby, the famous WWI dog, was not officially sanctioned by the military, he was smuggled over to France with the Yankee Division (with which my great uncle served in WWI, perhaps he knew him as we come from a long line of dog lovers) and they let him stay. There were some others.
From the U.S. War Dogs Association:
https://www.uswardogs.org/war-dog-history/types-war-dogs/
Breeds Used for Military Working Dogs
Early in World War II, as the Quartermaster Corps began training dogs for the Army’s K-9 Corps, more than thirty breeds were accepted. But later, with more experience, the list was narrowed to five: German Shepherds, Belgian Sheep Dogs, Doberman Pinschers, Farm Collies (short coat) and Giant Schnauzers. Rejected breeds included Great Danes, difficult to train because of their size, and hunting dogs because animal scents occupied their attention. Alaskan Malamutes and Huskies were still trained for Arctic duty as sled dogs.
Standard Breeds of U.S. MWDs Today
The vast majority of U.S. military working dogs in recent times are German and Dutch shepherds and Belgian Malinois, breeds chosen because they are very aggressive, smart, loyal and athletic.
German Shepherd dogs are preferred as the standard breed because of their unique combination of traits. Shepherds are intelligent, dependable, predictable, easily trained, usually moderately aggressive, and can adapt readily to almost any climatic conditions. While many dog breeds exhibit some or most of these traits, the Shepherd more than any other breed, most consistently exhibits all of these traits.
For specialized roles, detector dogs in particular, other breeds are used. Retrievers (Labrador, Golden or Chesapeake Bay) are the preferred breeds for One Odor Detector dogs.
All dogs trained and used by the U.S. military are procured and trained by the 341st Military Working Dog Training Squadron, Lackland AFB, TX.
Types have dogs have gotten bad raps when they become popular, especially via Hollywood TV shows and movies, due to over and bad breeding and handling. We've seen it with German Shepherds (Rin Tin Tin), Dalmatians (101 Dalmations), Collies (Lassie), Jack Russell Terriers (Fraser), etc. You almost hate to see an animal become popular on TV because you know it's going to result in a fiasco with the breed. But that's how it goes, unfortunately. Again, buyer beware.
Bottom line for me is, from the ASPCA article:
The reality is that dogs of many breeds can be selectively bred or trained to develop aggressive traits. Therefore the responsible ownership of any dog requires a commitment to proper socialization, humane training and conscientious supervision. Despite our best efforts, there will always be dogs of various breeds that are simply too dangerous to live safely in society. We can effectively address the danger posed by these dogs by supporting the passage and vigorous enforcement of laws that focus, not on breed, but on people’s responsibility for their dogs’ behavior, including measures that hold owners of all breeds accountable for properly housing, supervising and controlling their dogs. Breed neutral “dangerous dog” laws, “leash laws” that prohibit dogs from running loose off their owners’ property, and “anti chaining” laws can control the behavior of individual dogs and individual owners and thereby help reduce the risk of harm to people and other animals.
All dogs, including pit bulls, are individuals. Treating them as such, providing them with the care, training and supervision they require, and judging them by their actions and not by their DNA or their physical appearance is the best way to ensure that dogs and people can continue to share safe and happy lives together.
To that I will add increased awareness, education and resources on spaying and neutering the vast majority of dogs, which would go a long way to decreasing the number of unwanted animals euthanized each year and cut down on some of the over and careless breeding of undesirable traits.