Some things which people write or draw are certainly repugnant, extremely repugnant, including some particular forms of hentai manga, and if someone were actually acting out the activities described within, then I would want them to go to prison for a very long time.
But, committing a terrible act, and writing about it from a fictional perspective are completely different things. I don't think people are so brainless as to blindly follow what is happening in a hentai manga.
Someone doesn't simply "become" the sort of person who would do that, just by consuming fictional material, and if they're using purely fictional material, it could be even argued they're actively avoiding it.
The actual risk factors for abuse (and not merely creating / consuming prohibited content) I know of are:
Some people have poor mental health. Being unable to express yourself and having to shut things in would not help. Luckily, we have many ways to improve someone's mental health. Mental health can also improve if someone has supportive friends. This could be considered the main factor.
There are people who look for substitutes for a partner and unscrupulously pick that.
Someone may be physically incapable of feeling anything to adults and only to children. A recent scientific paper said that some address their loneliness by creating dolls and talking to them to keep them company. Banning and prohibiting things might frustrate them, but it wouldn't actually solve anything, other than making it clear that they have nothing to lose.
I am sure there are other possible factors, but I don't think I have ever seen "I saw it in a book" mentioned as one. Even Dr. Seto, who is a leading expert in this area, believes that those who would abuse, are those who would have abused either way, irregardless of this content being available.
As a response to your dead comment, not only do they not have feelings towards adults in any meaningful sense, other than making a friend, but they actually feel disgust and revulsion towards sexual settings involving adults. In a way, it is as if their sexual axis has been inverted, and instead of being disgusted by one, they're instead disgusted by the other.
It's also not a belief. The science has put it clearly that such people exist. Saying otherwise is to deny the science. Not only can the science measure someone's response to material, but even their neuronal response to it. It _is_ a spectrum, so there are types who aren't that bad off, and perhaps, even ones who are lightly touched by it. But, the idea that it is purely a form of deviance and twisting is flawed.
There are pieces of anecdotal science (studies on small samples of people who report it helping them not have to commit crime), a country level study on crime in the Czech Republic, and expert opinions from half a dozen experts which would suggest that at worst it is neutral and at best it reduces crime.
Most importantly, there has never been evidence that it causes crime. This property has largely been assumed, and has never been tested in such a fashion, despite a lot of people assuming it has been tested and produced such results. There is an exception where prisoners wanting to get early parole / better conditions play along with flawed studies.
According to Dr. Seto, those who commit crimes are largely antisocial individuals who were leaning and moving in that direction to begin with. And that they ultimately would have reached that conclusion.
At most, I might advise putting a content warning on a site or a piece that explains that it is a piece of fiction, and that it should be not be enacted. But, I've never seen actual evidence, only conjecture, that that it could be a problem. It's just not listed in actual psych profiles.
And while I will condemn someone acting out the crimes, condemning someone for consuming / producing a piece of media is going to feel like an adversarial attack on them (which fuels in-group bias, meeting up with like-minded people, distancing, and conspiracy theories), and it ultimately just deprives them of pleasure, without any real gain (and that is in the best case).
If someone does feel it is making them really likely to do something that they shouldn't, I would strongly advise that they don't read it, and I don't feel that a level-headed individual would just run all the way to doing a crime.
As for those reviews, I would have to know what they actually say. But, people say all sorts of things when they're "horny". And critics will critic.
But, committing a terrible act, and writing about it from a fictional perspective are completely different things. I don't think people are so brainless as to blindly follow what is happening in a hentai manga.
Someone doesn't simply "become" the sort of person who would do that, just by consuming fictional material, and if they're using purely fictional material, it could be even argued they're actively avoiding it.
The actual risk factors for abuse (and not merely creating / consuming prohibited content) I know of are:
Some people have poor mental health. Being unable to express yourself and having to shut things in would not help. Luckily, we have many ways to improve someone's mental health. Mental health can also improve if someone has supportive friends. This could be considered the main factor.
There are people who look for substitutes for a partner and unscrupulously pick that.
Someone may be physically incapable of feeling anything to adults and only to children. A recent scientific paper said that some address their loneliness by creating dolls and talking to them to keep them company. Banning and prohibiting things might frustrate them, but it wouldn't actually solve anything, other than making it clear that they have nothing to lose.
I am sure there are other possible factors, but I don't think I have ever seen "I saw it in a book" mentioned as one. Even Dr. Seto, who is a leading expert in this area, believes that those who would abuse, are those who would have abused either way, irregardless of this content being available.