As nasty and convoluted as they often seem, your remark is a prime example of why I respect the regulations of my country.

Milk of the Poppy I learned from Game of Thrones.

The use of "milk" for these plant juices has been driven by the marketing arms of huge corporations, not historical use.

Source? Afaik, coconut milk and soy milk have not only been made for centuries, but also called something like “milk” where they were consumed (e.g. India, China, Thailand, etc.)

ETA: The Mahābhārata, a book dating back to 400BCE, refers to making rice milk. So...

https://books.google.com/books?id=ivQ6CwAAQBAJ&pg=PT14&lpg=P...

Is that a translation preference or is the word for milk used specifically?

That excerpt is talking about deceiving someone with dilute pounded rice served as milk.

I don't know about soy milk, but that's not true at all for coconut where it was consumed.

Human breast milk is also called milk but it’s definitely a different thing.

Different how? It's definitely no less "milk" than cow's or sheep's or goat's milk. As a substance it's definitely as much "milk" as it can possibly be.

Are you serious?

You do know why animals (including humans) produce milk, don't you?

Yes, my point is it tastes very different, I’m not sure I’d want it in my breakfast cereal.