No need to get yourself so worked up; it only works against you(especially when it gets to the point where you forget to paragraph). Anime attracts people from all over the spectrum, so it's only natural you'll see people defending real life incest(and it's not exactly the worst thing you'll find anime fans defending).
Personally, I do agree that every variety of incest is wrong and perfectly deserving of criminal sanction(I'll give you cousins). But we're not exactly a legislature here and this thread isn't voting on a bill to legalize it, so, again, it's not worth getting too excited over.