I think a major reason that pornification is as heretic a topic as it is is because western society is a majority monogamous culture. I see the concept of "true love" being popular to be proof that our society idealizes and strives for a monogamous relationship that is continuous, as in: staying with one partner for life. Since undying loyalty to your partner is essential for this, porn is bad because it's hard to draw the line of where you are loyal to your partner and when that loyalty ends. Are you cheating on your partner by watching from a screen? What about VR? Will watching porn become an obstacle to developing real relationships?
These are the reasons porn could be bad in a religious sense.
Changing perspectives, a key factor to note is that visual porn, which I assume to be the primary topic here, is primarily consumed by men, as compared to romantic porn by women. You can imagine the former to be in the form of videos and pictures and the latter to be in story telling (50 Shades). As long as we are targeting porn for men specifically, it's reasonable to assume that the root problem of this conversation is male behavior.
I need a fact check on this but one idea is that porn was a driving factor in the development of the internet today. The reason the internet and its surrounding technologies was developed to this point today is because of men's desire for porn. The point being, porn is a viable substitute for men's biological desires for women, which should be men's ultimate biological goal. This desire, is what pushes men to work and develop so that society can progress.
So readily available porn that eliminates the need for men to work hard and develop things for women is problematic, though how much is debatable. It seems that a real relationship is preferred over purely porn, but is largely subjective and depends on you and your partner.
Some statistics show that countries that allow porn seems to have much lower rape crimes than countries that don't. This makes sense, as men can blow off steam more easily, there is less need to commit crimes for it. This seems like objective data that shows porn is good (Again fact check is good).
At this point I'm just throwing out ideas, but I want to finish with a heavy personal concern I have for porn. Namely, that people who are indulging in porn frequently seems to have a need to pursue more and more extreme and specific porn, seemingly getting radicalized in the process. Many of these are harmless but some are unsettling. Porn can be facilitating people to enjoy murder and torture sexually. Then the question becomes: can there be a point where porn is not enough, and they'll act on it in real life? I'll link a picture of a meme with a bunch of terrible porn tags and you can choose to look up these tags
at your own risk.
A counterargument is that these people would've derived pleasure from it without porn but I'm not so sure. I hate thinking about it but I'm curious what people have to say about it.