I can only speak from my perspective and from doing very little research on the subject. This is more a notion that I've been having in recent years that I think oddly fits into this discussion. For one, I don't condemn porn at all and in fact enjoy it very much (I mean, c'mon, who's ever seen it and NOT liked it? Someone I'm sure, but still), but I can say that anything in excess is a bad thing, even something as benign as watching videos. Now, I wouldn't say porn corrupts your soul or anything, but part of me does feel that the rise in certain sexual tendencies is linked to the ease with which porn is accessed, and the frequency with which is viewed.
As an example, speaking as someone who's 30, my young adult years without a computer involved waiting until crazy hours of the morning, just to get to see some breasts and butts. Yes, this is what it was like relying on cable and TV, and I remember vividly the thrill of this. It stuck with me, thankfully, but the more I've discovered and delved into the world of kinks, the more it seems like I require more in order to, well, 'have a nice start to my day'. I'm still very much a fan of seeing just naked women, however, don't get me wrong! It's a feeling that you never get over, but that's me as very much a straight dominant male who's a feeler. It just sticks with me.
Now, my concern comes with people who've been gobbling up choking, spanking and degradation scenes from the start. This also applies to a broader scope where it feels like powerful people also would want things that are out of the ordinary because the mundane no longer satisfies or pleases them. I'm not justifying this, I'm just saying that perhaps a lot of evil associated with sexuality has to do with the moral of the Portrait of Dorian Grey - taste everything enough times, and you'll become desensitized to this. That is the only moment when I sort of raise my finger and point out that perhaps mainstreaming sex and porn the way that we do isn't as good and freeing as we think it is. At the end of the day, it feels like humanity is in it's teenage years as it goes wild and sees how many lines it can cross. Spoiler alert: not every line should be crossed, but we cross them so we can learn the lesson, I guess.
An interview with Lisa Ann actually covers some of this, and it's a great listen if you're just curious about how old school porn vs new school porn compares, and the mentality behind it.