I just don't see what could even be considered indecent about Karina. The game itself establishes that she's 18, and only one year younger than the other core group of characters (MC included). I completely understand if some people don't like her as much as others, but I don't see how anyone could or should feel shamed in any way for liking her. It all comes down to personal preference, and that is different for everyone. Is it because she's shorter than the other girls? Is is that her tits aren't massive? I've known girls five years older than myself that look like they could pass for early teenagers, and early teenagers that look like they could be in college. Height and breast size don't determine age on their own. Maybe it's just me, but I think that variety is nice, and honestly, when everyone else has basically the same cup size, it can kinda start to get a little boring (for me, at least). If you don't like someone, that's fine. I didn't like Susan at all. I know a lot of people didn't like Leah at first either, but look how far we've come on that front. Everyone's got things they like, and things they don't. But we shouldn't shame or feel shamed for them (within reason, there are definitely things that don't belong at all). Not when it comes to girls in this game. For everyone that loves Alice unconditionally, I totally get it. I do, too. But I also like the other girls. That's okay. We're not choosing one over the others (yet) much less anyone over Alice, so saying that we like someone that isn't Alice shouldn't be something that gets questioned. That said, it's not necessary to post all the time about how we do or don't like someone just because we feel like it.
TL;DR - Everyone likes who they like here, and that's okay. We don't need to judge.