Yeah, I agree. You generally want things to be easy to understand, more so if there are significant consequences for getting it wrong. Making sure that allergens are properly listed lowers the risk of someone accidentally buying something they shouldn't.

Also, while this case is pretty obvious, is important to always insist that all major allergens are listed. Otherwise companies will slack off or make bad calls about when an allergen is obvious. It's like with guns: You should always treat them as ready to fire even when you think you know they're not because a mistake might get someone killed.