How do you know that the chap in question isn't the same with everyone? Is it easy to determine if he performs the techniques with the same intensity with all his partners, be they man or woman?
Obviously, I can't speak for all the blokes I've paired up with who have been like that, but I know for a fact that some of the guys who have been my sparring partner have either been excessively gentle/soft when compared to their usual way of sparring, or have been overly rough. I know it through either watching them during partner work and observing their normal manner, or through talking to other people (men) who have been paired with them.
An example was one chap who came to train with my karate club. I was senior student and the only BB female. The guy who came to train with us was a brown belt, but had been at brown for years (had moved between various dojos but never graded for black, for various reasons).
Anyway, we were doing some one-step sparring at one point in the class and Sensei had used me as uke to demonstrate the techniques he wanted to do. As it was a mixed grade class the focus was on keeping it simple and apropriate for the lower grades, but with an added 'twist' thrown in for higher grades to work on.
I can't remember the exact combo of techniques we were working on but it was probably something simple like a basic block and then strike such as punch or backfist. I do remember that higher grades had to use a locking technique on the end of it. Anyway, I was paired with the new guy and when it was my turn to attack he used a lot of force when countering and excessive force when performing the lock. I tapped my 'free' hand on his arm to signify enough and that he was hurting me but he ignored me and proceeded to hold the lock on for a further 8-10 seconds, causing pain.
I didn't say anything to him (I can take a bit of pain and thought that maybe he hadn't felt me tap) but when we practiced the technique again and he did the same again and then again afterwards I said something to him about it. His response was along the lines of the fact that it does people good to feel pain and that weaker people (from his meaning I knew he was talking about women) shouldn't be protected from 'reality'. Now, I'm all for a bit of reality, but there's practising a technique well and then crossing the line into deliberately injuring your partner and he was well over the line.
Class continued and we kept swopping partners for various drills.
For the last one-step drill of the session I was paired up with him again. This last technique Sensei had said to the higher grades to use our knowledge to add 1-2 apropriate techniques to the simple drill he was teaching the lower grades.
The other guy was hitting excessively hard again, but I wasn't saying anything to him about itand just carried on training until the final time through when it was his turn to defend. He performed a block, some counter attack and then proceeded to kick me straight in the groin.
The worst of it was he was pretending it was an accident, but he couldn't stop himself from smirking as I was bent double and trying not to spew (yes guys, it does hurt as much for a woman!! lol).
It took over 2 weeks for the swelling in my groin to go down and longer still for the bruising to fully heal.
Some might say that I should have blocked his attack, but the idea of one-step sparring is for the attacker to do one attack and for the defender to block and counter-attacked without being counter-blocked. It gives the defending partner a chance to have a "sitting duck" target who is there to be attacked - a useful sparring tool for lower grades to help develop correct technique and apropriate targeting as well as learning appropriate contact when working with a partner.
IMO that guy used excessive force when sparring against me for the simple reason to show off and to prove he was stronger and better than a mere woman.
Downstairs, after class one of the other guys came up to me and said "we're not all like that you know". I think the poor chap was thinking I was gonna have this real negative image of male martial artists after my experiences with this one eejit.
Thankfully I've trained with so many great male martial artists, decent guys who respect my ability and my time in training and who in turn I respect back, to ever let my experiences with a few numptys taint my view.