They are deep-pocketed, and they may be participating in a war, but certain words have technical definitions that are important to maintain when it comes to substances we ingest. Labeling anything as "milk" that did not come from the mammary glands of a mammal is technically wrong. Labeling anything as "mayonnaise" that isn't produced using poultry eggs is technically wrong. Labeling anything as "cheese" that isn't made from milk (see milk definition earlier) is technically wrong. Regardless of how evil you think these corporations are...they're not wrong in this case.
People have been referring to white plant excretions as "milks" for hundreds of years. Coconut milk, milk of magnesia, etc. Hell, almond milk was a popular ingredient in the Middle Ages.
But you'll also notice that language has changed a lot since the Middle Ages. This is a natural process, and no amount of prescriptivism or pedantry will stop it. Calling things that are not dairy — but that we use in all of the exact same ways as dairy milk — "milks" is not a problem.
Yeah, just the other day I bought some chocolate eggs and when I went to fry them up for breakfast it turned out they were chocolate (wtf) this mis-labeling of things is just too confusing.