The article about Barbero was about the difficulties that horses have recovering from broken legs. As you may know Barbero did not survive,and he only had 1 broken leg,that was not a compound fracture.He went through colic and several infections and finally had to be put down due to laminitus.
Horses are very delicate creatures despite their size. A horse the size of most Throughbreds weigh about 1200 lbs.,and their legs are not much bigger below the knees than a normal mans upper arms. So you end up with half a ton standing on toothpicks.
Also like the article mentioned horses have very delicate constitutions, they react badly to anesthesia,and they have problems with antibiotics.If they eat a food that their system is not used to,or they don't get enough water,or they get too hot,or they get too cold, they will colic. This is not like a human baby that has gas on its tummy. Horses can not burp or throw up. Everything has to go out the other end,and it is a long trip!
Often times the gas does not make the normal "trip" and settles in the horse's hooves,and then the horse "founders",or gets laminitus. This is so extremely painful for the horse that they can not stand on their hooves,as the gas causes the hard hoof to separate from the horse's "foot",and the bones in the foot literally sink because of the loss of the support from the hoof. Most horses that suffer more than a very,very mild case of laminitus have to be put down,due to the fact that this stretches all the tendons and joints in the horses hooves,pasterns,and hocks(because of the bones in their feet and legs being out of their correct position). The horse that suffers this will never be sound again,and will be in extreme pain for the rest of its life(which could be made even more painful by the horse colicking again because of the pain it is in.)
Eight Belles had compound fractures in both front legs, there was no way to give her enough pain killers to get her to be able to stand long enough to get her to a vet surgery. You can not physically support 1200 lbs,3/4's of it supported by the front of the horse on two legs that are 4 feet away from where the weight is carried.You would be causing the horse unbearable pain to move her,and there was no chance of saving her life with surgery.
It was by far the kindest thing to do to put her down where she fell.