As M.Red said, it's just a video game. I think the devs simply have to pick and choose what would be sensible - from a gameplay standpoint - for crafting requirements. I remember that in Ark, spoiled meat is used for a bunch of stuff that seemingly wouldn't make sense in the real world either. Entrails from Draugrs can be farmed or simply accumulated very easily via Iron grinding, so it's actually great that they are used for sausages since you're likely to have tons of Entrails. It's just what is available. And perhaps sausages requiring boar meat only would be too easy for early game. Just my opinion.