One might argue milk the same way. How can people call almond juice milk? That argument seems to me as ridiculous as the meat argument. There's several wild edibles I can think of where the inner core of the plant or root is called the meat. It's been called that since I can remember. And this fits well within the definition of the word "meat". The word seems to be flexible enough to cover veggie burgers in my humble opinion.
Definition of meat
1a : food especially : solid food as distinguished from drink
b : the edible part of something as distinguished from its covering (such as a husk or shell)
2 : animal tissue considered especially as food:
a : flesh sense 2b also : flesh of a mammal as opposed to fowl or fish
b : flesh sense 1a specifically : flesh of domesticated animals
3 archaic : meal entry 1 sense 1 especially : dinner
4a : the core of something : heart
b : pith sense 2b a novel with meat
5 : favorite pursuit or interest
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