Hi there,

I am new here but want to say something about the original question of this thread: Why so much nc and M/f?

I think it is biologically and psychological induced.
First of all sex is stimulated by certain hormones which also have a major part when aggressive (e.g. adrenaline).
Second the role-model of the man, mainly thru education but induced by nature, comes closer to the dominant side in stead of submissive side.
The female by her role loves to be conquered, play the submissive. In reality they sometimes feel frustrated about this behavior (feminist).
The idea to defend herself against aggression stimulates her hormone-production as well.
The man on the other side is celebrated for his conquest and feels good about it when successful and is by nature stimulated more eager to have sex.
So in my opinion aggression/violence can enhance sexual stimulation.