Attention to detail: "([a-z]+) milk" != "\1milk"
> It must be because the code you linked only tells part of the story. I'm guessing...
The entirety of CFR is public domain, readily accessible, regularly maintained, and conveniently searchable at great expense to taxpayers. Care to explain why your speculative assertion isn't supported by proper citation?
What's the point of linking to the FDA definition anyway? Apart from it obviously being a result of lobbying, it's completely irrelevant to the question of whether or not plant milks are, well, milk. It is overly specific as is, for starters, nobody would deny that mammals other than cows give milk.
The only result following from the regulation you linked is that people selling milk can legally only drop the specifier "cow's", but not "donkey" nor "almond", before the word "milk". Plant milks will keep being milks, as they have been in the English language since at least the 13th century.