“the burger is grown from a cell of a live cow”
It doesnt have to be
“. Shechting it would defeat the purpose,”
that depends what the purpose is.
If the purpose is to have cheap meat it wouldn’t defeat the purpose (in the long run). IF the purpose was to have pareve meat and this is deemed pareve, again it wouldnt defeat the purpose. If the purpose was to minimize slaughtered cows then shechting one and creating, say, 10 cows worth of meat wouldnt defeat the purpose.