It was kind of sarcasm.

Anyways the family tree wasnt in ETW (or if it is I cant find it) and people didnt seem to care nearly as much then as they are now. Probably because the royal family werent really commanding generals as I recall and it made no difference whether or not you knew who your cousin. But here it actually does matter especially with the political system which is probably why they didnt think people cared about it so much, which is probably why it doesnt make an appearance in this game.