Different cultures have different ideas of what "child friendly" means. As an example, Sailor Moon was targeted at 8yr old girls in Japan but deals with topics that many parents in the USA are not comfortable with for 8yr olds. For example lesbian relationships (I'm not making a judgement on that, only pointing out the fact that many USA parents would object to that topic for their 8yr olds and in fact that facet of Sailor Moon was edited out of the USA anime version).
Another example is One Piece which is also targeted pretty young but nearly every female character dresses super sexy and one of the main characters smokes at every opportunity.
Also, in general manga != for kids. There are tons of very adult manga and I don't just mean porn manga, I mean manga about adult topics targeted at adults. There are similar adult comics in the USA but the selection and market is arguably a order of magnitude or more larger (by percentage) in Japan.
Another example is One Piece which is also targeted pretty young but nearly every female character dresses super sexy and one of the main characters smokes at every opportunity.
Also, in general manga != for kids. There are tons of very adult manga and I don't just mean porn manga, I mean manga about adult topics targeted at adults. There are similar adult comics in the USA but the selection and market is arguably a order of magnitude or more larger (by percentage) in Japan.