I don't know what point of mine you are trying to disagree with, or what you are getting at. You seem to be missing the forest for the trees.

Everything you have asked about has a very straightforward answer, but you lack the philosophical context to see that.

It's like asking a chemist to explain molecular bonds, when you don't even know that atoms exist.

As I've said, the proper principle of government is to protect individuals from the initiation of force by others.

Since the reasons for this principle are out of the scope of this discussion, yes, you could certainly find some way to appear to pick on it and score points, yet actually fail to do so successfully.

Nonetheless, correctly applying this principle means that if something is always a poison to everyone, it's not a legitimate product. There is no legitimate use. Producing it and selling it is simply initiating force.

On the other hand, if something is a legitimate food, it's fine to sell it.

There is a separate question about allergens. It is an allergic person's responsibility to make sure they don't ingest allergens.

The government forcing people to label things is an initiation of force and a violation of rights.

Absent such regulation, there would still be plenty of food producers who make information about food content publicly available, since it is needed by their customers who have allergies, and for other reasons.

In the cases where food producers do not publish their ingredients (in which case, probably nobody should consume the food...), people with allergies would just be out of luck.

It's not clear whether you are actually advocating this kind of interpretation of Ayn Rand's position or not.

It seems to me that the principle of government being solely to protect individuals from the initiation of force by others is a great one, and should be the primary one. For bringing this idea into my consciousness, I am grateful to Ayn Rand and those who propagate her work.

However, "sophacles" doesn't seem to be arguing against the principle. He or she seems to be arguing against a simplistic interpretation of its implications.

For example you say: "correctly applying this principle means that if something is always a poison to everyone, it's not a legitimate product. There is no legitimate use. Producing it and selling it is simply initiating force."

Who decides what is a poison to 'everyone'? Well since by the correct application of the principle, it is the government's responsibility to protect individuals from this initiation of force, it must therefore be the responsibility of the government to recognize these situations.

Does that mean that the government needs to set up a science infrastructure to decide what is harmful to 'everyone'?

If so, how is it to staff this infrastructure with scientists, and how is it to decide who is qualified to do the work? Perhaps it needs to establish an education system for this purpose. Given that working as a government scientist by necessity means giving up a lot of time that could otherwise be spent securing shelter and provision for the future, perhaps the government should set up a way to house and provide for its employees in their old age... and so it goes on.

I'm all for the principle, seriously. I just don't see how it helps to offer unrealistically simplified interpretations of how to apply it to people who are interested enough to engage.

Unless you really do think that Ayn Rand had a perfect and complete prescription for the best of all possible societies...