And given there are work arounds, I don't see Incest as a "Risk factor" that was going to have the game stopped, so I attributed the comment of it "Being safe from incest AND other things" as "Safe from things I don't like."
Well, most of these work arounds (patches, hidden activation, etc.) aren't safe on paper, either. And the safe ones, like the player determining relationships, quite often impact the whole writing negatively, so they should be avoided in my opinion.
Anyway, as far as I see it, incest is certainly a very accepted fetish. The only time I see people really pushing back against it, is when players want to add "their" fetish into a game, where the dev didn't plan add that kind of content in the first place. But that's basically the case for most fetishes...
I mean, incest in WaL! would be kinda futile anyway. Yes, you could add some kind of sister or mom character later on, but I'm not sure that would really please those, who actually like the whole topic. It's a bit like NTR, where it's only really good, if it's an important element of the game.