I've brought this up in social circles when I've related love scenes in movies to this type of porn.
I don't know why porn does this. I don't partake in watching/looking at porn as consistently as I used to, so I'm not sure if the trend has remained. A few friends in high school preferred (at one time) heterosexual sex between a male "performer" and a female "performer" - most of which was shot in the mentioned manner (OP). I've never been given a clear answer as to why.
Another friend of mine put it this way, "Why would you want to watch some guy doing what you want to do [regarding sexual intercourse]?"
That's pretty much what I concluded as well. I find heterosexual porn more funny than anything else. It's so incredibly fake: there's tons of shots of the guy just loving his life, ramming and pounding away, as focused as a sniper like he's doing something that requires massive amounts of skill and attention (you know, as opposed to being an inherent instinctual behavior/act). There's tons of shots of the gal just taking it like a champ, but wincing like she's thinking 'maybe this wasn't a good idea...', and it becomes uncomfortable for you, as the viewer, because you get the feeling that maybe something is wrong. There's always a weird, tilted, stylized zoom-in to the guy's face when he's about to release and he looks like he's going to have a stroke - as if what he's feeling is just so amazing and nigh impossible to achieve, and he's never felt anything like it before!
Everything is overemphasized and exaggerated to a comedic level. I don't get the appeal. As the OP stated, it's clear that they're targeting heterosexual males. For the better part of the last 40 years, that's been the target demographic and verifiably the largest consumers. So why on Earth do the producers/directors/camera crew feel as if the consumer would want to see a guy's anything during the video/scene? I can understand the reason for seeing parts of someone, sure. It takes two to tango and it's unreasonable to expect the male to be completely out of the picture, but it's a far cry from being the anonymous penis in the video to camera-hugging the guy's face and abdominal/groin region and changing the point of view of the entire movie entirely.
I do find it funny though. Both the over emphasis and the fact that my peers, save for one or two, would be completely transfixed and enthralled with what was happening on screen. Whatever, each to their own.