If you buy into our sex negative culture hook-and-sinker, then yes I guess it would be thought of as "common courtesy". That said, I do agree being sensitive to others is a worthwhile endeavor...to a point.

Personally I would never have the hubris to speak for "most women". In my experience the variety of willingness to be vocal during sex is pretty wide. And as for me, I tend to enjoy the ones who can be unselfconsciously vocal about enjoying it any day. To each their own I guess.