Patreon have not always had those strict censorship rules, it started out as a platform to support any creative artist, but a few years ago they got pressure from multiple sides, such a Paypal, Governments (won't name any particular country..) etc. to change their low level of censorship.
I remember it vividly, because I was then a keen member on Patreon, supporting multiple erotic game creators. When their mail about rule changes came I predicted they shot themselves in the foot, because a large part of their income would have been from the erotic genre, lets face it, porn sells!
The first weeks after their rule change was havoc, many creators got auto banned simply because they where creating a game with sex in it, they could only come back after a personal review of their content.
To make it worse, non of us, members (Patrons) and creators got any warning time, it came from one day to the next.
It's not just incest they are against, it's any kind of fetish/kink which the watchers of morality finds "offensive".
They also restricted their search engine to make it harder to find erotic games on their site, one of the reasons I landed here btw
So why is Patreon still one of the main payment platforms used to support creators?
The answer is simple: They got credibility, people trust they won't get cyber-robbed if they add their credit card info.
A new site would have to build up that kind of reputation before it could become successful and I assume a lot of paying platforms, such a Paypal, would not accept a censor free site, since they have a strict non-porn politic.
Personally I'm against censorship, it strangles the creative mind.
The reason for those rules is not that Patreon, or whomever pressured them into it, can't see the difference between fantasy and reality, it's because they are afraid that players (that's us) will begin to think that incest and the like, is acceptable (or even normal) in real life if we get too exposed to it.
The porn movie industry also changed around that time.. suddenly it was Step-this and Step-that to get around the incest restrictions, and if any one knows how big the market is for that kind of movies it would be the porn producers
As a mature, sensible man, I'm against incest and sexual crimes of any kind in real life. But when it comes to fantasies that's a whole other ballgame. In fact, my fear is.. if we don't get to ventilate our kinks through games and the like, it could manifest itself in the real world. But it seams useless to debate psychology with the high and mighty watchers of morality
Anyways, my point was that Patreon hasn't always been so strict.
About this games new version, I think I'll wait for a future update as it appears there isn't any sexual content yet, so thanks for the heads up on waiting for 0.4