> In the US, packaging is guaranteed to have an accurate "contains" section.
You are incorrect. The labeling laws have a number of loopholes which fail to appropriately or accurately list ingredients. No guarantees are made and it can hardly be called accurate.
Yes this impacts lives, and speaking as one from the afflicted cohort, labeling is a joke and has no measure of trust to begin with. For example GRAS ingredients in trace amounts often don't warrant being included in the label, there are weight cut-offs, and only known major allergens (of which relatively little research is done in proportion to other endeavors) are excluded from these loopholes. Natural or Artificial Flavors can be any of many different ingredients on a long list.
To top this off, these same laws may or may not be enforced with any consistency when the products are used as intermediate inputs (and originally processed outside the US). They often don't test for traces except in highly debased markets (such as honey), or after a consumer lab brings it to their attention.
There is also no distinction between size of the ingredients which impacts safety; and this can be important. For example, asbestos isn't harmful until it gets really small where it then can lead to mesothelioma.
Titanium Dioxide is often used as a food additive, but there have been no safety studies done since they began processing it using nanoscale particle sizes.
From what I've seen in the literature, they did these safety testing on large particles before modern advancement, and simply claim the smaller particles are the same (implicitly) without proper controls or testing to verify. This is often allowed under the self-certification of safety loophole as Beyond Meats did with the gene edited beats/heme.
Also, since they changed requirements to new anti-trans fat oils in processing I can't eat out anymore because the oils (which need not be disclosed) induce dermatological and inflammatory issues that manifest visibly within 1-2 hours. They are GRAS and I know many people who suffer from this including most of my extended family. Little research has actually been done/published.
To put this all in perspective, given all of these confounding issues, labeling already is nearly completely useless and lacks consistency to begin with. No claim of consistency can be valid until you are consistent in these other areas first.
> I get that this is a pretty clear example that it contains milk.
You literally cannot make "butter" any other way. Margarine is not butter. Garlic Butter is made with butter, Shea butter is a cosmetic and in the name says what it is derived from; you don't have rational people calling shea butter, butter. These issues fundamentally go to all language and by extension definition.
The word butter has a historic and common shared meaning absent adjective modifiers. It is distinct (unique), and definitionally made from milk.
This is the def'n from Oxford Dictionary.
-A pale yellow dairy fat used in cookery and as a spread, made by churning milk or cream and straining off the buttermilk to leave a solid substance.
Inherent in the product description (name) is the fact the fact that it is derived from milk and will thus contain milk products.
> Couldn't I say the opposite
First that's not the opposite, and second you can say anything and what you say has no bearing on the truthfulness (people can both lie and tell the truth, and the fact that they can do both doesn't indicate one or the other).
In this context, no that would lack any real meaning, and end up being flawed reasoning which relies on the same false justification as the other line of thought, the forgone conclusion that there was trust to begin with, and the reason-ability.
You can justify anything circularly, all the way down to delusional madness, false and truth cannot be determined without external objective identity.
The structure of circular reasoning fundamentally fails objectively since there is no externally based identity (definition), and worse the structure abuses the contrast principle of your and reader's psychology to make it convincing despite it being fallacy, and delusion if you were to accept it as truth. These techniques are well known, have been abused for centuries, and often involve strategy to create convincing lies and deceit.
Inducing and misleading people towards delusion isn't something rational or good people ought to do, but there is benefit in promoting deceits following such structure, since not everyone can do the mental gymnastics (discriminating against intelligence), and it allows greater accumulation of power left unchecked (leading from the "banality of evil" to the "radical evil").
Complacency often mentioned in the banality of evil, is after all a form of sloth (a deadly sin, and warned against because of its destructive influence).
People lie all the time today, often without knowing, and believing and justifying lies as truth is the definitional path towards delusion. Schizophrenia diagnosis rely heavily on the fact that delusion is prevalent in the people being diagnosed, and techniques and related structure originating in torture induce delusion involuntarily.
The outcomes related to delusion, given sufficient time, are always destructive.
Finally, the world is not a safe place, nor can it be made so. There is inherent risk in everything you do. Those that would seek to make a safe world, inevitably and blindly through complacency tread and limit agency, where those same people would then support and seek enslavement, and death for all given the right opportunity.
They would do so because they wouldn't know better because they have willfully blinded themselves to the consequences of their own actions, and in so doing unknowingly violate oaths and beliefs they claim to hold dear.
The latter characterization is a valid characterization for describing evil people (willfully blind people) who commit evil (destructive) acts. They need not believe that they fall into this label categorically, but objectively and externally as an outcome the truth remains unchanged regardless of belief.