One thing you have to remember is Japan is very much different regarding laws compared to the US.  For example the consenting age in Japan is 12yo.  For the US that is unheard of, but it's how their laws are.  With that said, Japanese art has always been controversial with Lolicon, Shota and the like.  I for one think their art is fantastic but thats just my opinion.  I like the freedom of expression and versatility.   With  their laws the way the are, you can definitely tell that they're more liberal than the US.
Adrian