I only got a half-hearted "Oh. Sorry about that".
This line is a red flag the size of the red sea!
I have years of mixed sex martial arts behind me, so I have both told people, and been told by others, to drop the power. Never has a woman responded in such a desultory manner. I have only ever encountered this from a small minority of men, and in the context of other interactions, it's because those men wanted to hurt their smaller, weaker opponent, and were using martial arts classes as a pretext to get away with it in a socially acceptable way.
Their expectation and hope is that you will be too embarrassed to speak up. You're supposed to accept that being beaten up is the price you pay for even trying to improve your own self-defence skills. It's not.
No-one improves his or her own skills from using brute force on a smaller person, and no-one gets better at self-defence from being used as a punching bag. They only acquire injuries.
Some people (who have never been on the end of this) always try to defend this behaviour as "preparing for a real life crisis situation!" I'm sure there are some people lurking, thinking that right now. To those people, I say:
Would you pay someone to throw your non-swimming five year old off a boat into the middle of the Atlantic Ocean? I mean, swimming lessons are supposed to prepare you for worst-case scenarios like a boat sinking. So why not start by throwing five year olds off boats into freezing water? Think of the money that's to be saved by skipping all those years of carefully graduated classes at the local leisure centre!
Or what about booking your child's first ever riding lessons, but booking the fiercest, most bad-tempered stallion in the county, because you want your child to be able to handle horses like that as an adult?
Martial arts classes are the same as both swimming and riding- you need activities pitched at the correct competence level in order to progress without unacceptable risk of injury.