I've rolled with really high level girls that were ligther than me, and been tapped repeadetly.. I've rolled with girls that just plain suck at grappling too. Doesn't matter to me. Everyone is in the gym to learn self defense, and a sport.
Provided a man has had a girlfriend at some point in his life, then physical contact with a woman shouldn't be that big of a deal. It's not a sexual scenario either. When you grapple you focus on winning and defending, it's a pretty pure thing.
It's a non-issue to me.
The very idea of people not wanting to roll with another person because that person is of another sex just seems beyond weird, and retarded if you ask me.
I could understand it if said person belonged to a very strict religious group, but that wouldn't make it any less stupid.
I guess there could be several reasons, but I think the main ones would be ego or insecurity.
A friend of mine met a girl in a match a few weeks ago, and he asked me; "Omg Joachim, I'm competing against a girl, what do I do? Fuck!"
I told him; Do as you always do. Don't loose, don't go lighter, don't go harder, just get her and that's that. No biting, scratching,tit-slapping or cunt-punts!
She had very little grappling expirience, so he won easily. I still don't get what the big deal was. We automatically asume that girls are inferior, but in grappling that's not always the case. There are fewer girls, and even fewer that are really competent, but at the end of the day, in the same weight class, technique and expirience wins.
And if they aren't good enough, that's their problem. No girls are gonna get better by guys rolling too light with them all the time.
That's my take on it. Oh, and if I were a girl and guys at my gym refused to roll with me, I'd be pissed.. wtf.