Eating duck only makes her a cannibal if it's an intelligent duck. Or amongst any fringe dietary groups who think intelligent beings should only eat plants, because, like, animals feel pain and they're our brothers and sisters! We can't oppress them by eating their babies and taking their milk and wearing their skins on our backs. Plants are, like, what we're meant to eat! Plants don't feel pain, and, like, they can provide us with everything we need...

And then the DM sends in the trees...