I actually prefer the emergent common usage philosophy of language, but that also supports my position. 

Your argument, as far as I can tell, is just “because I say so”. 

Ahhh, neologisms exist definitely.
I guess some people believe all they read just because someone with relative importance says so..
Its ok Simon. You can use marketing fueled words as you like.

It's way less precise, when the definition of milk includes "the liquid made from some plants and trees or their nuts, etc."

Those plant milks are definitionally milks. They are not, however, saps.

charts_and_numbers

Dairy vs. Plant-Based Milk: Which is Greener?

suraz

It's way less precise, when the definition of milk includes "the liquid made from some plants and trees or their nuts, etc."

Those plant milks are definitionally milks. They are not, however, saps.