You're taking the whole incest thing to literally.
To understand the "incest craze", you need to remove the incest and look at the character relationship, and then you'll understand the core that appeals to the subset of the male demographic that is enjoying this sort of stuff.
You get the relationship where the older male acts as a pseudo-authority figure and provides guidance to a younger inexperienced, vulnerable, adorable female that often cares a lot for the male, dots on him and is reliant and dependent on him even if she denies it, eg. a tsundere (but this point of appeal is a whole nother story).
Even the LN/anime highlighter in the article makes a point of this; Kirino is shown fawning over adorable imotuous in her VN games as she puts herself in the shoes of the protagonist. BTW, in the aforementioned series, the protag develops a romantic relationship with a different girl, not his sister Kirino.
Sexual overtones are just the cherry on top. Sex sells and everyone knows this. The targeted demographic are young men who are horny, almost to a fault.
Taboo themes can be interesting and titillating to the right person, not just because of incest, but just because it's something forbidden.
In the shows themselves the incest is a short cut to easily setting up this sort of relationships. How else would a young guy get to be an authority figure to a younger female?
I once read that imouto anime is made for guys who don't have a little sister, and I agree with that. Those who are not actually into incest are detached from that aspect and focus on the fantasy of the sexualized relationship of dependence and caring after the girl.
2 ( +3 / -1 )