When did this ban occur? Because I've seen people streaming Senran Kagura, including the latest game that just came out. I mean, it has hosted streams of the series for a long time now. Must be a very recent change.

I don't think this has anything to do with "ethics" as GGers might suggest, but this decision does seem like an odd choice on Twitch's part. Senran Kagura as a series has a lot of fanservice and can push it at times, but it actually does have a heavy gameplay focus, as well. That's particularly true of the latest entry in the series, which has some pretty technical action and multiplayer.

In the past, Twitch has discouraged explicit visual novels because the primary gameplay is minimal, with the result being explicit scenes. Yet, Senran Kagura has a lot of gameplay alongside "ecchi", rather softcore content. The games are rather suggestive and can be sexist at times; though, that could be said of a lot of their biggest games. Unless they were tipped off that it may get a AO rating when it comes to the US(which I'd doubt; though, I haven't quite seen how far they push it in Estival Versus), I'm not sure why they'd cut off streaming the series at this point.

Regardless, it's ultimately Twitch's decision what they want on their platform, and they can avoid any games or content that they want. If it's a sticking point for some, they can go use hitbox or something else. If they respected the freedom of companies to decide for themselves, GGers should respect Twitch having their own rules on what games they do and do not allow on their own site.

On a personal note, I'd just question why they banned it now. I mean, the big problem on Twitch is streams and chat full of toxic garbage, not suggestive action games or even visual novels. In my opinion, if this was meant to at all help clean things up on Twitch, their priorities would be a bit mixed up.