I personally see nothing wrong with this since everything is covered no matter what else is going on (notice this is just a still image, not a video of her gasping and panting and doing a lot of suggestive stuff but with everything still covered, that would be NC-17/R but not Adult rated).
IIRC peppy recommends everything in this game to be PG-13 (some material may be inappropriate for children under 13), meaning this isn't completely meant for children but is totally safe for people above 13 and below 17/18/21/wutever it is where you are, so I don't see what's wrong here really, if the bg at the time of this writing (meaning it isn't already fixed) is only viewable for adults then I think hentai shouldn't be viewable at all anymore.
Maybe I have very relaxed standards, but that's just my opinion on the matter, don't hate me because of it.