Regardless of the fact that incest is repulsive and immoral for most people
To many, perhaps, but I don't think "most" is fair to say, at least not as a fact. Morality is entirely subjective, as is whether or not you are repulsed by something. I understand the illegality merely from a public health perspective, as too much inbreeding results in some pretty unpleasant results. There are quite a few places around the world where if it weren't against the law there would be more people partaking of it openly, and in the US at least, having come from England and other UK-dominant countries where the obvious results of inbreeding had been known for years, it's no surprise why it's illegal in most of the states. We did inherit a lot of the 'common law' from England, afterall. (how their royal family is German now confuses me a little, but I was shit with most history).
In any event, outside of procreation purposes, I have absolutely zero issue with it. If MC is going to bang his daughters, that's fine, as long as he's not actually producing the next generation, even if a one-off from particularly young women is virtually foolproof in terms of results.
And for the occasional player who isn't a complete deviant, there's always the harlot from the restaurant, or coworkers, to be diddled with abandon. I like the woman at the restaurant. She's bold, and almost shameless. Respectable traits, fuck what other people think, do your own thing.