[Viennacon]

Moral norms are there for a reason. There is a reason we don’t think incest is a good idea.

[Tax-chick]

There is a reason we don’t think incest is a good idea.

I believe the author would argue that, if incest is your way of being in the world, then that is your moral judgment, and it is just as valid as anyone else's moral judgment and way of being in the world.