I am glad there is becoming more awareness of emotional abuse. It is very difficult to prove in any sort of legal way but children are susceptible and it is easily hidden.
While I wouldnt go as far as calling it “abuse” I had a coach growing up who would give me the silent treatment if I upset her. Once at a show in front of one of my idol trainers/judges/BNT told me I “ruined that horse” because it stopped with me several times at a small fence. It really to this day has messed with my confidence. She also gave me many many opportunities I wouldn’t otherwise be able to afford and she made me a strong rider. You were never ever to be “disloyal” to her, which meant trying any other discipline or liking any other coach - and so much much more. It wasn’t until my late 20s that I realized how warped some of that behavior really was and our parents had no idea it was going on, but as juniors we were very susceptible to it like any kid who adores their coach.
I am by no means saying coaches shouldnt be tough on riders - I work with young athletes now and there is a certain degree of mental toughness and discipline needed to excel in any sport, but modeling good mentoring behavior is so very important.