ITT: lots of people wondering why this is an issue at all when obviously butter contains milk.

It’s because the company can effectively print whatever they like for the name of the product with no regard to the actual ingredients. A consumer needs to know what they’re actually buying because of things like allergies and intolerances.

In this case, and depending on the severity of the allergy, that missing ingredient warning could cause someone a bad case of the farts or something as serious as anaphylactic shock.

This being said, I’d still agree that people not wanting to consume milk should stick to products with positive confirmation that it is milk-free.