This debate won't end in a hurry. We've been arguing about what beer is since the German beer laws and before. British Sausages cause hilarity in Europe. The idea that definitionally we can state a-priori what is or is not the current meaning of a term when language itself is plastic is kind of broken because the distinction between Cows, Cattle, Beef, Veal, Bison, Oxen, Bullock and Bull, Buffalo and Bison and Cow, G…
You're conflating metaphors with obfuscation. For example, coconut milk is named so simply because it's a white liquid. It's not trying to be a replacement for milk, or trying to confuse people, it's just a metaphor. But vegan milk, sausages, etc, are all meant to be as similar to the real things as possible so as to cause confusion.
I don't think Apicius was trying to sneakily confuse non-vegans when he said "lacte nucis".