i don't know why it's so hard for people to get their head around the idea that lions and tigers are apex predators in their environments and we're not. i think it's ultimately a religious thing. even humans that aren't religious have held on to this idea of humans as being outside of the food chain, but the evidence in front of our faces just simply does not uphold this. i mean, in the video they talk about animals and humans as though they're two entirely different things that don't naturally mix in nature. a moment's reflection should indicate how absurd this really is.
there's actually mounting evidence that humans evolved as prey species, and primarily for lions (or the ancestors of modern lions) in the african savannah. the predator-prey relationship that developed may even be the dominant factor in how we evolved intelligence, both culling the human population of those who were unable to escape and providing a selective factor for those that were able to figure out how to not get eaten, whether we're talking about individual or group behaviour alike.
it follows that what you're seeing here is ancient behaviour that goes back millions of years and defines what we are as a species, not something that's developed recently. there really couldn't be anything more natural than humans being eaten by lions. it just might require adjusting your understanding of humanity's place on our planet to get your head properly around it.