It Goes Around
I can think of two teachers (KC & JN), one of whom taught the other, both of which share the delusion a)this isn't abuse at all, and b) they're not the coward, their uke is.
This is analagous to child abuse cycle when the abused grows up the abuser. He equates abuse with acceptance, and seeks to recreate that feeling of home.
Sound sick? It is. Get the *** out of there. Don't let the cycle continue.
Anyone, instructors too (holy as catholic priests they may be), who take the trust and arm of a willing partner and violates it is a coward, and there is no room in budo for cowards, period.
So yes I have heard about it, and it embarasses me as a teacher and student.
Get out of there and warn others.
What city are you in? I'd guess you're in the UK somewhere.