That doesn't make them good, or justifiable. We are all descended from murderers; that doesn't make murder good. It's always happened, it's currently happening, and we need to stop it.
The moment we sit down and start singing Kumbayah some neighbour will take his chances to sweep us up. If ever we were to manage to tame the entire human race into singing Kumbayah we'd be taken over by a fleet of flying saucers, sapient gorillas or just rebooted because the simulation entered a state of deadlock. It isn't just humans either, strife and conquest are a fact of life from the most primitive life forms to homo sapiens and everything in between.
To that point I think indigenous societies were doing just fine. It wasn't a fact of life to lose a language or entire culture within a generation before settlers arrived. You didn't inherit a position of serfdom. Property rights weren't a thing. Women could get divorces and had political authority. In many tribes non-binary genders were accepted or even the norm. Tribal warfare did not kill millions indiscriminately.
Entropy may be a fact of life, you don't have to contribute to it more than necessary. If we are already warring with things like flatworms and COVID maybe warring with each other is counterproductive and a "dark pattern" to be worked on. Food for thought
In other words, Rousseau was wrong, the savages have the same vices and the same virtues as we have. Wake up from your dream of the perfect past which came to an end when the evil white man came to conquer and welcome to the real world. Read some real history instead of Howard Zinn and Nikole Hannah-Jones, have a look into the different forms of slavery as practised by those "indigenous societies", read up on the Aztec's own claim of sacrificing 40.000 people over a 4-day period for the re-consecratino of the Templo Mayor in Tenochtitlan or the 50.000 to 200.000 (historians quibble over the actual number) who were sacrificed every year. Heading into the temple complex your eyes would be drawn to the steep double staircase on the Grand Templo Mayor. A trail of blood leads to the impressive top of the temple, a flat working area where the captives or the occasional volunteers were brought to be sacrificed where most of the city could see. Most of the temple-top sacrifices involved cutting through the abdomen and diaphragm to rip out a still-beating heart. Not to paint them with a black brush, just to realise those "indigenous societies" were just as "guilty" of "sin" as all others.
Wake up.