Japanese idol-pop is generally really pop & cute. this also goes for guys as well in most cases. clean image and innocent looks are what these idols go for. they are
made to be marketed to children, teens, and young women. their fanbase are girls. it's not so much a Johnny's Entertainment or Hey! Say! JUMP thing, but it's universally known. however there are idols that are more mature and appeal to everyone, women & MEN, like JE's own KinKi Kids.
i do think Hey! Say! JUMP are geared towards their own age-range. the 15-20ish range.