1. Moral agency: Humans can reason morally, and (at least in theory) strive to act morally. Lions are not capable of that (afaik)

2. Necessity: Lions have no supermarkets. 95% of the people reading this can most definitely go vegan (and 99% vegetarian). Just like how self defense and murder are different.

3. Non-existence: 99% of the animals we slaughter we also artificially bred into existence. It's a false equivalence, because those animals wouldn't even exist

4. Practicality: Regulating wild animal feeding behaviour would be stupendously difficult. A vegan world on the other hand is not just possible, but also better for everyone. In zoos, where we can control "wild" animals, we already reduce suffering by not feeding live prey.