Having had a lot of different breeds, I have to kind of disagree with the above statement. Most any breed can make a good FARM dog, but LGD's are different than any dogs I have ever experienced. They LIVE with the stock, and accept the flock/herd as their pack. Their behavior towards them is decidedly different than that of other breeds. They have a very low prey drive, yet will defend with their lives. Most breeds if overwhelmed by a predator such as a cougar, or other large foe, will normally back down. An LGD will continue to protect. Hence the need to choose your LGD numbers according to predator pressure.
There is nothing wrong with a good Farm dog though. It's just a different need and a different type of protecting.
It's just a misuse of the term. Sort of like confusing a Thoroughbred with a purebred. They can be mutually exclusive.