While I'd concede to the idea that it certainly sounds simple, nothing in life really ever is.
What we're seeing here is compromise -- a concept lost on many today. Rather than completely throw in the towel, they're playing with a loophole that will allow them to put the main character into a loosely reasonable situation without treading on the boundaries set by Patreon. The author's intent should be apparent, but considering they haven't explicitly stated that it is in fact incest, it still leaves them open to be able to host their content while receiving revenue. Does this mean they have to sacrifice some details in the story to abide by these rules? Yes, it certainly does. Does it mean you, the player, understand the implications of the situations described any less? As far as I can tell, no, it doesn't. This one detail is easily surmounted by the player's ability to understand context clues and know that maybe something else is being implied.
Crafting a detailed storyline and a complimentary world takes a lot of time, which is something that doesn't come cheap. The developers are still people with financial and physical obligations just like you. They want to be able to create something that's well worth your time and theirs. Knowing that it takes time and dedication to do so, the most rational route would be to monetize that time spent making the game. I understand it can be frustrating having the characters ostensibly portrayed as roommates, but if they hadn't written it this way they most likely wouldn't have been able to deliver updates at this frequency with this level of polish as just a small team.
The barrier to entry for this title is as small as the suspension of your disbelief. If the idea of them dancing around the subject matter to remain on the platforms that allow them to operate in the first place is this much of an issue, there's other games out there that explicitly state that incest is one of their themes.