I do not watch a porn, I did so only few times long ago, then it was a hentai.
As opposed to porn, hentai is mostly about story, tho it can vary.
We should stay away from content presenting ''pure evil'' content and be careful about borderline one, which can be considered as one in anime/hentai.
To ban it at hw lvl is too much, if even laws of countries allow that, not to mention God/Jesus did give us freedom with pointing at what is sin, so even laws of countries banning that is too much, not to mention just hw/sw company.
Looks to me more like they just apply their personal preferences as limits.
Its hard to define borderline, so they just banned it altogether and don't care...
Well, apple is closed system, always was, funnily, bitten apple as a logo indicates pretty opposite pov, so its kind of ridiculous...