Read my comment more carefully. I didn't make that claim.
I claimed that if you make a distinction in your morality between animals and plants based on their ability to feel pain, you have that duty. (Note that this is a claim about the consistency of a morality, not about one particular moral system.)
If on the other hand your morality does predicate your moral right to eat something based on its ability to feel pain (as our ancestors did), then there is no such duty.
(Of course there is also a grey area between these -- a morality based on a creature's ability to express an experience of pain is more broadly accessible.)
I claimed that if you make a distinction in your morality between animals and plants based on their ability to feel pain, you have that duty. (Note that this is a claim about the consistency of a morality, not about one particular moral system.)
If on the other hand your morality does predicate your moral right to eat something based on its ability to feel pain (as our ancestors did), then there is no such duty.
(Of course there is also a grey area between these -- a morality based on a creature's ability to express an experience of pain is more broadly accessible.)