I mean, it’s two definitions for the same word. And it looks like mammary secretions is the older version, I think. Additionally, personally that is what I think of when I think of milk. I think of almond milk as an emulsion of almonds that approximates milk and I think most people agree with me.

That said, I am not going to confuse almond milk for milk unless they just straight up call it milk.

Bare minimum research: https://www.etymonline.com/word/milk