I'm not jumping on either side of the argument about if Japanese are the nicest or not, but there are certainly some major differences from "nicer" western countries, with some of them hidden behind courteous outward appearances. In addition to common problem of assaults on women there is the whole child porn thing in Japan which strikes me as particularly egregious. Possession of it wasn't made illegal until 2014 and people were given one year to dispose of any they had. Apparently it has not disappeared, with record numbers of cases being reported by police in the three years since the law was passed [1].
[1] http://www.newsweek.com/child-pornography-and-child-abuse-ja...