What would worry me are not the games themselves, but feeding your child's interest and involvement in the whole anime genre.
...the hell is wrong with that? o_O
It leads (and is designed to lead) to a lifelong preoccupation with Japanese cartoon culture, which is totally amoral.
No, it's not. The Japanese certainly developed a different moral code than us Westerners, but they have a moral code nonetheless. Therefore, they would hardly be "a-moral".
Eventually (and sometimes it doesn't take very long), this leads to preoccupation with manga and hentai...
Dunno why you're grouping all of manga with hentai, which is simply a sub-genre of anime and manga. There are hentai anime and manga, but it isn't all that way. Not by a long shot.
Let me tell you something else. I've been into anime for over 10 years now, and I have yet to develop a hentai addiction. I mean, I know it exists, but I don't really care to watch it.
...which are aimed at older kids...
Anime is aimed at adults, too, not just kids. And I doubt any hentai series has ever been directed at children.
...and which often involve the vilest pornography imaginable, including cartoon child pornography, which is enormously popular in Japan.
There is some pretty vile stuff that can get turned into hentai (or so I've heard). As for child pornography, are you thinking of the whole "lolicon" fetish? I find it kind of disturbing, but at least those girls are animated and are not real girls. :\
As for actual "child pornography, which is enormously popular in Japan", citation please.
Even in the "mainstream" anime world, the occult and, very specifically, homosexuality are treated as normal, acceptable parts of life.
As far as I know, most Asian cultures really never had a negative view of homosexual/transgendered people. But specifically speaking, I don't really know how homosexuality is actually treated in modern-day Japan. I had a friend who seemed to think they weren't all that accepting of it outside of anime.
As for the occult and Christianity, well, the Japanese simply view that like how we'd view Buddhism or Hinduism. A lot of symbolism turns up in anime, but it doesn't hold the same meaning for the Japanese that it would for a Westerner.
At any rate, a great deal of anime was (and is) not originally produced for Western audiences. There really wasn't much of a market for it until recently, with the advent and popularity of Toonami.