The thing is, the entire situation was likely blamed on the horse and the man learned no lesson at all. People like that seldom do. All I can say is that at least the horse got a bit of revenge before being put on someone's plate.
As for how often that happens, you might be surprised. A horse's first instinct is to flee whenever it is confronted with danger. If it is unable to flee for whatever reason (in a stall or a pen or tied up), then all it's instincts will turn to fight and it will kill to eliminate what it considers a threat.
Even people in countries like the US, with easy access to information and knowledge, have problems with this. They get a horse that is very fearful and they push it too far too fast with desensitizing or handling and the horse will pin it's ears and charge. Then the people run away and the horse learns that is the way to get humans to leave him alone and it becomes habit.