Senran Kagura - That's danger close to hentai territory!

I've seen enough Splatoon fan art to know where this is going.

Copy-pasta from myanimelist:
Alternative Titles
English: Senran Kagura Ninja Flash
Japanese: 閃乱カグラ

Information
Type: TV
Episodes: 12
Status: Finished Airing
Aired: Jan 6, 2013 to Mar 24, 2013
Producers: Artland, Genco, FUNimation EntertainmentL, Media Factory, Marvelous AQL, Senran Kagura Partners
Genres: Action, Comedy, Ecchi, School
Duration: 24 min. per episode
Rating: PG-13 – Teens 13 or older

The biggest reason I can think of is that most of the characters are younger than 18 (japaneese law of consent is 13 but porn is still 18+). Wouldn't work so well overseas.