Because I hope that someone who's hands were required to assemble the recipe didn't blindly add ingredients like "bleach" if the AI happened to hallucinate them.
For a super simple example, if you don't properly handle or cook raw meat then you risk getting sick even though the food might not immediately taste bad. Maybe that's obvious to you but might not be to the person preparing the food. Another example: Rhubarb pie is supposed to be made with the leaves and not the stalk because the stalk is poisonous and can cause illness. Just kidding, it's actually the other way around but if you were just reading a ChatGPT recipe that made that mistake maybe you wouldn't have caught it.
Edit: it is irrational to think this way when someone prepares your food¿