> should probably be probably labeled contains no milk.

What about other products that contain no milk? Shouldn't they do this as well? Should every package list what it doesn't have?

> that one standard line of text

This is the point. The packaging is entirely up to the manufacturer. Should the FDA approve every food package before it's used? We obviously can't do that. What we can do is mandate a few "standard lines of text." So that regardless of the packaging decisions consumers can still determine the facts quickly and _reliably_.

Think of people with allergies that have low vision or any other handicap which would make all these "good enough" ideas become dangerous.