It can be avoided. It's an available choice for the player, reached only after refusing other options. Anyway, this is wrong on many levels, I think. First of all, it barely makes sense from a narrative point of view. It's the first real sex scene (that is, with vaginal penetration) and it comes with the newest, less developed character. There is barely any relationship established between the MC and the aunt, and the context for this to happen is... well, the less said about it, the better.
I don't like rape scenes; and especially when they come with physical intimidation/abuse, like this one. I think, up to this point, the game bordered disturbing or disquieting content, but this scene clearly goes head first into it. Always a bad idea, despite the delicacy of giving the player the option not to take that path, but, taking into account what has been going on with Patreon in the last few weeks, it doesn't seem to be the brightest course of action.
Maybe, and I'm just speculating, it's a thing he implemented due to some patrons asking specifically for it (I know some developers do that). But, apart from the fact that I don't like that content, it seems to me that this is the worst possible moment to do it.