Wow Monica! I would be upset to see that too. There are poor trainers in every aspect of horse training. Just dont judge all by one bummer. And actually even a twisted wire snaffle COULD be an easy bit IF the rider has a light hand. It is the hand/s of the rider that determines if a bit is severe or not.
Reining horses must go on a very light - or loose rein. Ideally they stop and turn with shifts in the rider's body weight for cues. Many are started out in hackamores for the precise reason that they want a light mouth.
Too bad you saw the results of some poor rider - that I wont honor with the term 'trainer'.