yeah i definitely realize that there is a big problem with the anime community in general with supporting unhealthy romance like abuse, incest, and pedophilia, it's just that i usually just stay in my yuri corner and it's frustrating to see stories like that taint the LGBT community's public image. i definitely don't think that stories featuring gay people should all be bland happy picturesque fairytales so that the straights dont think we're sinners or whatever, but romanticizing abuse and incest and pedophilia is deplorable no matter what. ESPECIALLY since the LGBT community is so associated with pedophilia and """""converting""""" children.
What were you saying again ? Oh, right : maybe if you're talking about real people that argument would hold, but this is fictional.
Also, this here isn't exactly incest as those two girls have no blood relation. They're only step-sisters because their parents got married barely a few weeks before the start of the manga. They didn't even grew up together. Heck, even the whole premise of the first chapter is that they don't know anything about each other and have to learn living together
As for the whole "abuse, incest and pedophilia", in my experience most anime fan who enjoy those genre do make a clear distinction between what happens in their animes and real-life. Sure, there will always be some exceptions, but saying that those who enjoy incest or lolicon story would do the exact same in real life is basically saying that those who enjoy action movies featuring solving your problems through killing everybody who opposes you would as likely pull out a gun when facing some trouble. Or because you have fun playing a game like GTA, you're going to do the same thing in real life.
And that kind of content extensively exist in non-yuri work anyway, so those who bitch about the gays about it are just using any excuse to bash that community. remove those and they'll just find something else to "prove" their point.
All in all, when it comes to work of fictions, it's important to keep in mind that it's just that : fiction. Not reality. You yourself pointed out, but kind of in reverse. Because even if this work were actually incest, well... It is fiction. If you don't like the premise, best not read it entirely, as you do with citrus (which share a similar premise to this manga, by the way). And really, you're talking about incest, pedophilia and so on about a manga that is not incestuous as it's about step-sisters that met a few month agos and are around their sixteens.