“From her injuries, it’s obvious she was chained up and backed into a corner, because the wounds are only the front of her. They do that to bait dogs — board them up in a pit hold in the ring so the fighting dogs can come at their faces.” SourceWhere do they get this stuff? A "pit hold"? Backing dogs into corners?
This dog is scarred because she fought like a normal dog - with her mouth and teeth pointed directly at the face, neck, legs and chest of the dog in front of her. Generally speaking, dogs do not aim for the butt when they fight. The vital spots are up front and it's best to keep your teeth where a) it will do the most damage and b) it will protect you from the most damage. That's, of course, if you are really fighting for your life.
Yes, it's possible this dog was a "bait dog", but I think it's more likely she was either used for fighting or was a scrappy terrier. She's still a victim of human negligence (possible cruelty), no matter how you look at it.
Also, just because a dog fights or was fought does not mean they are irremediably damaged. The former is perfectly normal behavior, the latter is a gross exaggeration of that normal behavior. It does not in any manner, shape or form indicate a dog is unsound, unstable or unadoptable.