Incitatus32, not antropomorphizing at all, rather trying to understand the horses' behavior. As for the aggressive horses you describe, maybe the training (yours or the one they received prior to meeting you) wasn't ideal for the horses that they felt so threatened they went to the attack-strategy. Not all methods work for all horses, not all trainers work for all horses. Nothing wrong with the trainer, nothing wrong with the horse, yet sometimes, if it's a misfit, the result might be desaster.
Our first horse was a rescue horse that had lived with bulls as sole companions for many years. She did not behave like a normal horse at all, and she would show aggression if she didn't like things. She was 12 when we got her and had not learned anything a horse needs to learn. Our riding teacher back then was a really great guy, I still think he was awsome with horses, bought sour horses from the big sports and retrained them to be great school horses. But our horse did not get along with him, hated his guts. When she was new in the barn, he wanted to show her to some people and went into her stall. She attacked him, he had to jump over the side wall to save himself. When she only heard his voice she'd get excited. He once had to hit her over the back with a broom (and we would never have complained about it, it was self defense), made her hate him more.
This horse never did anything to us other than nudge us with her head (one of the few things we couldn't get out of her for the rest of her life). We trained her to be a sweet trail horse, we were able to put little kids on her back and she'd watch out for them. She DID get a few licks with a crop over the years since she DID behave like a bull at times and tried to just run people over (potentially dangerous disrespect), but most of the time you had to treat her gently, with little pressure. I remember another occasion where some "more experienced" girls tried to show us how to lunge her (with pressure and "do as I say") and she charged at them, as well. Still that horse was so good if treated right that my parents let me trail ride her by myself as soon as she was halfway trained.
Another example, my mare, when she was first trained at age 3, started to rear and seemed to be dominant and dangerous. Curiously, when I trained her with the help of a Parelli-oriented trainer years later, she was the sweetest horse from the start (I'm not a fan of Parelli, but it worked good for her). She seemed to just have outgrown it. However, once she got very excited when I walked her out in the fields near herds of other horses. In order to get respect, I flicked the rope pretty hard and sent her back. After two or three times of this, she started to rear (just a little). I was quite shocked. When I thought about it later, I figured I had actually overdone it. She is a very sensitive horse, and what I did was too much. She had no escape, and she felt threatened, so she went to rearing.
The trainer told me another sad story of how at the ranch she used to work at in Canada, they sacked out the young horses in the round pen. Like it or not, it worked great for pretty much all the horses. Except one, who was part Arabian and had a personality much different from the average Quarter. He worked himself into a frenzy, tried to escape and broke a leg. Different horses, different characers, different treatment required. Some need a firmer hand, some need more sensitive handling. I seriously doubt any horse's problems derive from not getting enough beatings in their life, though. Not enough leadership, yes. I'm not the perfect leader (far from it!), so my horses show disrespectful behavior sometimes, like not getting out of the way right away or "discussing" if they want to do what I ask them to. But I wouldn't try to beat that respect into them. Rather, I try to work on being a better leader to them.
Okay, I hope that was not too much blabla and I got my point across, it's getting late over here...