Just because it isn't being provided to you by the government, doesn't mean it's banned. The government doesn't provide people with cars, by the same logic we could say cars are banned. Clearly that isn't the case.

They aren't freaking out, they are just lying to be able to peddle adult material to children. It's not about Manga in reality, it's just another scare tactic when we all already agree that material should be censored for minors. That's why we have movie ratings, TV ratings, and children's, teen, young adult, and adult books. What the people crying, bans, really want is to expose young children to adult books.

The government, not providing manga for you to read, is not a ban. As a parent with children of various ages, I routinely monitor my children's anime and manga reading and prevent them from watching certain ones. As someone who has watched all of the shows listed, I would not want many of them in elementary or middle school, which, I'm guessing most of these were no longer being provided for. Likewise, some, like Assassination Classroom, has a lot of material that would be incredibly questionable due to school shootings. While I've read and watched it as an adult, I have kept it from my 12 year old for to various issues with it and see no reason for it to be in a school library outside of high school. I can think of a few English literature books in high school that were assigned and were way more risque than it.