I haven't read the articles yet (I'll probably do so on Monday when I'll have some more time), but based on what you wrote about those articles I think they (and some of your own thoughts - which I agree with -) invalidate your very last sentence ("But that's in real life."). "Those of us who are mature enough" - that's exactly it. Sure, we know that it's just a fantasy, but some people (impressionable young male minds, as you put it) will think that that's normal, that that's how it should be in real life, and when even girls start acting like that because that's what they see in the media... (especially if those girls don't like it but they do it because they feel pressured to do it due to the media) that's just horrible. And yeah, I do agree that for some people, these fantasies actually help blow off steam and are a positive thing in that way, but, like I said, it can really mess up others. Unfortunately, the media can and do influence a lot of people just like you wrote ("there are a lot of stupid young men who are brainwashed by too much porn, how young women could feel pressured in now competing with the fantasy feminine ideal." and "More than 8,000 teen girls received augmentation breast surgery in 2014"). In fact, I'm pretty sure that the media and the pressure that it can put on people are in huge part responsible for my precious little Cyndi Wang ruining her looks... And so I think it would be great if there were more out there in JAV than just the aggressive animal and the M man, because, like I said, those two types of guys are the kind that I usually come across in JAV, which often makes it difficult for me to enjoy a film (although I tend to go for the ones where the guy is the "M man", because at least the actress seems to enjoy herself then which is a must for me). It would be really nice to see some guys who fall in between.
As for the different strokes - yes, to each his own, sure. Like I said, I do believe (and hope) that r*** titles help some guys live out their fantasies alone and prevents them from committing one of the most awful crimes, but I also think that it takes others down a very wrong path. In fact, I recall reading about a successful Japanese musician who got taken to court by a girl who said that he r***ing her, and then more than ten other girls (I don't remember the exact number) came forward saying that he r***ing them too.
Anyway, this is something that has always bothered me whenever I came across it, and Motiman's comment made it seem like the right opportunity to talk about it.