A great many of today's fans have never encountered the sex scenes. They're a tiny fraction of the original game, they're well-known as not being particularly erotic or well-written; they're really not important or relevant to the game's history or sales. A couple of sex scenes don't make a game "porn" any more than a couple of quips make a game "comedy". That you focus on them says more about you than it does about FSN.

One out of Clannad and Kanon has sex scenes in and the other doesn't. I can't even remember which is which, and it doesn't matter.