It's not odd at all.
If you'd read it, you wouldn't have had to ask the question, barring any issues in regards to reading comprehension... No, I'm not being facetious, that's already happened at least once.
With regard to reading comprehension, I think it's fair to say that a good deal of what's communicated via text is open to misinterpretation. Take for instance what I just said. What I meant was it was odd that
Perhaps the word I should have used is "unique." It is a fresh and innovative twist. At least I haven't seen it before and I've played...several...VNs over the years.
Now, someone with strong reading comprehension skills might realize that multiple meanings are possible in those few words of mine and not be as quick to resort to a sarcastic response. I get that you've answered the question multiple times and that might get old, but in that case you can feel free to just not reply and let folks arrive at the answer by their own means. That would save some effort and frustration.
You could also bring that morsel of information about how the incestuous relationship develops out of the often overlooked dev notes and give it a more prominent place in the description. That could also cut down on the questions. Whatever you decide though its poor manners to give people undue grief for asking questions just because the answer may be apparent to you. This is how we all learn.