it is written that way to avoid getting the game removed from sites such as Itch.io and Patron as they have rules regarding Incest which would make this game against their rules. It's easily fixed, there is a patch available to restore the relationships to the correct terms.
There are literally hundreds of posts on this page explaining the issue, find the patch and maybe read a few other comments before calling the Dev out on it.
Here is the link for patch if you can't be bothered to educate yourself.