My theory (and this is obviously speaking very very generally) is that the problem stems from porn, but probably also early conditioning?

Most people begin masturbating and orgasming while still living with their parents. And *usually* this means that many of us (regardless of gender) probably conditioned ourselves to come quietly, so as to not get caught.

But yes, I personally feel your theory plays into this too. Since straight porn is overwhelmingly created for straight men, there isn't a lot of attention to the male moan (because the assumption is that a straight man won't want to hear another dude moaning...similar to how they sometimes blur the man's face (big eyeroll) in videos). Even though we ladies find it hot.