I call that being an asshole, the type of thinking that coach has is to drill their students to dust and if they can't come back is because they aren't worth it, this is bullshit.
I know teenagers and even adults athletes can get arrogant if not hold a bit but doing this so much just because of little errors only grinds the person's self-esteem, more so in a young person, this coach is an asshole with an outdated mentality, to say the least.