The barn I ride at recently acquired a horse by the name of Trouvee. She is a lovely dunskin (buckskin and dun) Quarter Horse mare who is very well put together, with a sweet temperament.
She is also one of the most messed up horses I have ever sat on. She does not respond to normal leg cues, then over-reacts to the rider's heel (a clear symptom of a horse that has been over-spurred). Her reaction to the rein isn't much better. She carries her head up in the air and her back hollow. Worst of all, the first time they asked her to turn left, she nearly fell over. Her extreme tension has left her requiring chiropractic treatment and her left hind leg is so weak I joked that nobody had ever turned her left in her life.
I don't know whether I can go as far as to say this mare is a victim of abuse, because I didn't see it and I have no proof. But everything about her points to the fact that this sweet, tolerant horse has been ill treated. My guess, based off of the inability to turn left, is that they had her running barrels (barrel patterns are always run to the right), and never properly schooled or trained her. I can be absolutely sure some nasty spurs were used on her.
Yet, she still likes people, she still opens her mouth for the bit. Some people, like some horses, will stand the most extreme abuse for somebody they think they 'love'. I have no doubt that Trouvee was fond of her abuser (horses are capable of liking and friendship) and they repaid her by damaging her physical health and her sanity.
Most likely, they did so to win. To writers, we need to watch out for those who would abuse us in order to win. Also, we need to make sure we do not abuse ourselves in the quest to be published.