Humans only have an instinctual aversion to incest insofar as a natural instinct to avoid inbreeding. If they do not know someone to be their sibling, or their culture places less of an emphasis on incest as taboo... well, urges are possible. Just look at Oedipus and the Oedipus complex.
As for the subject of the ARTICLE- a very well written analysis. H-games are popular because they play to a fundamental fantasy that is close to us. Much like any pornography, the most popular ones feature stories with a basis in reality, and a vaugely undefined 'everyman' male lead that the masculine viewer can insert himself into the place of- someone perhaps not as popular (like the viewer perhaps), somewhat insecure (like the viewer?) and yet possessing of good qualities and a general positive disposition- unless your playing that hardcore shit that lets you be a terrible bastard or a rapist. Even this is fantasy that lets the player lash out in a consequence free environment.
Really the only thing that seperates an H-Game from a normal game is the H itself- and then not very far with certain mainstream titles! The embraceing of consequence free sex is the same as embracing consequence free violence- a way of acting out in ways we cannot, as a pressure release. These H-Games tend to have melodramatic stories because:
1. They are primarily Japanese, and melodrama is raised to an artform in the Japanese/Anime set, just watch Macross or Gundam. In this way, they are atypical of their culture.
2. All the other games do the same, and like with normal games the more successeful predecessors are emulated closely
3. The story gives a break from the pure sexualize content which allows the player to alleviate their guilt and shame at playing an H game, get more napkins, and take a smoke break. I keed- it engages the parts of the brain not captured by sex. Sex by itself gets very boring, as pack primates we seek emotional and social interaction. Even in real life, relationships based purely on sex quickly become stale and unsatisfying. These stories grant the pretense of emotional engagement that keeps people playing and buying, rather then just looking up porn on the internet or watching Backdoor Sluts 9.
