It doesn’t need to be invoked, the higher moral agency placed on humans hinges on the notion of superior human rationality. You could choose to be a vegetarian and choose not to kill animals, but that doesn’t mean that it is a more ethical or moral choice because human biology evolved to require meat other wise it requires planning and supplementation that is not necessarily possible outside of industrial societies. I do agree that choosing not to eat animals due to the industrial nature of meat production is a more ethical choice, but not that killing animals is necessarily wrong.

I may not be explaining it well but basically: the idea that humans killing animals is wrong can only exist if you think humans are superior to animals. I reject that notion and that’s where my argument comes from.

All life is supported by displacing or ending others. Even if you don't view plants as ethically problematic, the agricultural practices to feed civilisation, by definition, must upset the natural ecological balance and harm animals.

The reason a vegan doesn't feel upset about eating produce is the degree of removal from the animal harm. They don't see the deforestation or destruction of wetlands or the damage done by pesticides or in fertilizer production. It's no different than an omnivore not feeling guilt when a butcher kills an animal (even if they wouldn't do it themselves).

This harm has always happened since we developed coordinated agrarian societies. The most ethical stance is that humans should return to their natural ecological niche, hunter-gatherers with minimal reliance on agriculture.

However, veganism isn't possible in such a society. The ability to supplement the human diet with plant based alternatives at scale requires disruptive agriculture. Thus strict veganism* in this lens is inherently self defeating.

*The vegan concept of harm reduction isn't impacted here, there are still lots of reasons to go plant based

I'd like to see a single human alive today who because of their actions has not killed another animal? I guarantee every single human alive today has been responsible for killing an animal. Sure it might not have been for food but your actions have resulted in the death of an animal.