There's something so funny about extrapolating modern human behavior up to hypothetical alien civilizations. It's a part of our science fiction that hasn't changed much from the days when life on Mars or a water-rain soaked Venus was still Hard Since Fiction. Like, they even admit 99.99% of the video is imaginary -- but they can't imagine anything else? Silly.
At 5:32 they show this stylized progression from hunter-gatherers, to agrarian settlements, to modern cities. What's telling is that the agrarian settlements are bleak beige and yellows and oranges; poop and skeletons piled up everywhere. The modern city is a pristine and healthy green, with roads and airplanes and clean water. If there's any consideration to the consequences of present day life, it's a footnote. A bug to be ironed out in the next technological rollout.
They just love to end videos on a sort of 'Cosmic Call to Arms', where humanity goes on to colonize the stars. Never any consideration of what may need to happen before, the work and organization necessary to facilitate such a lofty undertaking. Modern problems are barely worth considering, because we'll just engineer our way around it, by Jove!
If it was just Kurzgesagt, I probably wouldn't bother to write this out. But it's the most prominent and competently produced version of a narrative that seems to be everywhere. There's also a lot of lefty analysis and breakdown of these tropes. But I think that's only half of the work necessary. You can't just shoot down a story and call it a day. You have to fill that space with a more compelling story, give people something to think about and contemplate instead. Otherwise the old story just hangs around, getting bigger and more silly with each refutation it survives.
The "Three Body Problem" sequel that spawned this jerk-off video posits a Sci-Fi-esque natural resource which all intelligent life values immensely. And it is the demand for this resource that ultimately drives interstellar conflict. Dune had a similar premise, although Hebert took it in a different direction.
I'm not totally on board Posadas's conjecture, simply because I don't think the social conditions for interstellar travel solve for interstellar xenophobia (either natural or learned). Its very possible that you can have a True Perfect Communist society on one planet while collectively expressing Fascist attitudes toward your nearest neighbor. Certainly, AES cultures are not devoid of their own inherited bigotries and historical traumas.
I just don't think any kind of First Contact is going to be practical from a very material sense. Even if we do somehow manage to pick out another civilization, rather than loosing them all in the background radiation of the cosmos, what can we do that's more war-like than simply waving at another ship passing in the night?
Assuming we aren't talking about life bizarre that it beggers human comprehension - a planet sized superintelligence like Asamov's Nemesis or Gas Giant inhabitants like Ben Bova's Leviathans of Jupiter or the unphotographical fungoid Mi-Go of Lovecraft - how much time and effort would it take for any human to so much as reach out and touch another lifeform? Stretching our fingers across the void that we might brush them across the gray appendage of an extraterrestrial would take eons. How would we even conduct such a war? At best, we'd just be flipping each other off from opposite ends of the galactic freeway.