My first TKD school had an instructor who caused injuries. I left as soon as I realized what was going on and found a school that focused on positive spirit and respect toward our fellow students.
The instructor I had at the time (mid-1990s) emphasized light contact to the point where our students took pride in having control. If you made contact with the dots on the chest protector, (and light touch to the padded helmet) that was good form. You made your point by pointing out openings with a kick or punch. We did not bruise or injure our classmates. If we were well conditioned and stretched adequately, very few students had injuries. We were taught to evade or deflect kicks - never hard on hard blocks because legs are stronger than arms. We worked on a lot of footwork and counter-attacks.
My current instructor looks the other way if students hit or kick each other in places that are unpadded. It really bothers me because that is not the way I was brought up in TKD. I'm used to getting a deflected punch or kick here or there but not full force punches or kicks that are off target. I consider that partner to be out of control and that would be the worst comment you could make about a TKD student.