First of all, I'm trying to get some clear information on the ban. So far what I've gathered is that law is trying to establish what's okay to sell to minors and what should be sold to adults only. So in this sense, I don't think it's a ban on manga so much as a clarification as to what's appropriate to sell to minors.
I think we all know from the selection of manga I chose for this group that I don't choose series with even modest amounts of violence or sexuality or series that depict inappropriate acts towards minors. In my private life I do read manga that I would consider outside the scope of this group, but I don't read or watch any manga or anime that I would consider gratuitously violent or sexual. In general, I believe that adults should have the right to choose their entertainment as long as it doesn't harm anyone. As for minors, I believe parents should help their children choose appropriate material and that parents should know what their children are reading.
The question for me comes down to what can harm other people. I am against the depiction of harmful acts to children either real or drawn unless it is in the service of the story and that story has something to teach. There are a great many stories where a character's childhood trauma shapes the personality of the character. These are important stories to tell (for instance "I Know why the Caged Bird Sings".) However, I don't approve of stories that depict such things for shock value or titillation. This doesn't mean it should be ban, it just means that I will not consume it. I don't believe that violent or sexual material drive deviant behavior, rather I believe people interested in deviant behavior seek such materials out. It's easy to blame an outside influence for crimes rather than to blame the person themselves. I will say, though, that rape and murder existed long before people drew it, so purging such materials will not make one ounce of difference.
As for homosexuality, homosexuals exist. Get over it. Again, adults should be able to choose their entertainment and parents should help their children choose appropriate materials. However, for parents, I think if they know their child is struggling with questions of their sexuality, that it may be a comfort to the child to read material that affirms that struggle.
In general, I have a great appreciation for artists who are able to convey trauma, tragedy, violence, and sexuality without actually showing the graphic details of it. I feel it's best to leave some of these things to the imagination. In this sense, I think the Japanese law is an invitation for artists to try harder with their story telling. Seriously, how many more stories do we need about students in relationships with their teachers?
I'm trying my best to find some concrete facts about the law and when I have located some reliable sources, I will share them with you all. As of now, though, I think it's too early for any of us to get riled up or believe anything out on unvetted manga blogs and websites. Everything I've seen so far has been hyperbole.
If you have a concrete vetted source of info, please leave a comment. If you have some thoughts to share on the matter, also leave a comment.
