I've read The Devil is a Handsome Man since it was on discovery.
They made lots of changes in the story and how it started. If you look at the first chapter, a newcomer would think it was a R-rated comic (maybe even think it was like 50 shades of grey), but actually it almost doesn't have sex scenes, since there are lots of terms on LN you have to follow. Then as new episodes comes, any fan of romance comic would think the story is confusing, since they are expecting to see some sex scenes, kisses, etc, but what they get are lots of small talks, like real life, then at the end a cliffhanger that is related to the story itself.
TL;DR I believe, if your comic is R-rated, there will be changes that fits PG-13 rated, it can insinuate something, but don't show any parts, at least it's what makes me think when I read the featured comics. And I think they don't add other genres, like crime/mystery which is what The Devil's Handsome Man is about... So they stick with the "Romance" genre, since it's very popular and can attract more viewers/readers