I've just had a similar case with porn mangas involving young girls and rape acts. Our law isn't so clear about it.
Those mangas can be as disgusting as the 'real thing' but nobody got hurt in the making and if it allows pedophiles to relieve the tension caused by their urges, it is not so bad after all. But it can also give them ideas and be a temptation, I dunno.
However, the law needs to be adapted IMO because if anime child porn is considered illegal, then a movie depicting a rape or a murder is illegal too.