Mars has no indigenous population, and seems to be plenty big enough for everyone.
What makes you think the interaction between the first and second wave of colonists wouldn't run into all the same problems that we had on Earth?
(Not that I believe there will be any waves of colonists. It'd be easier, and have a better social ROI to make the ocean floor, Antarctica, Mount Everest, or San Francisco hospitable to human life, than it would be to settle Mars.)
At least whatever intelligence may explode in future (if it does), it will be hopefully pure logic with no strings attached as we, humans have - emotions, tribalism, sex, psychology, physical bodies to take care of, aging, racism, ridiculously low output bandwidth, so many things that AGI wouldn't have to deal with. I hope that it can optimize on a global domain and not get stuck in some local optima.
One very effective way to achieve survival is to build your "self" out of many independent competing subsystems, and select only those that themselves survive. An individual human does not particularly care if some of its cells die; the point is for them to die, such that the overall human remains healthy (when they don't, you get cancer). An individual cell does not care if some of its mitochondria die; this happens naturally at times of low energy use. An individual mitochondrion does not care if glucose molecules are broken down and reconstituted into ATP; that is its function.
On the other end of the spectrum, an individual corporation does not care if it ruins the lives of some of its employees by laying them off; such callousness helps improve the efficiency of the organization itself. A healthy economy does not care if the individual firms that comprise it go bankrupt, because this is the only way to free up inefficiently-used resources before they drain the whole economy of its vitality.
A lot of things that suck come from competing interests across the different levels. To the corporation, layoffs are a good thing, and the share price goes up when they happen; to the individuals laid off, they're a tragedy. At the species level, evolution is what gave us the richness of biodiversity we see; at the individual level, it gives us death and fruitless competition to pass on our genes.
If the machines manage to take over, it'll be because they manage to evolve this fractal competition within them, in which case they'll just replicate human foibles at the lower levels. (Won't somebody think of the poor software libraries, replaced by a shifting package.json?) If they don't evolve this, they will themselves remain tools, subject to replacement at the whim of their human masters.
Earth has been in a continuous state of a global war in stasis for longer than I've been alive. The fire under that pressure cooker isn't diminishing as far as I can tell.
If it's going to be child's play, how come none of the attempts to achieve an ongoing sealed biome have been successful? Nearest so far was the Soviets in the seventies during their lunar programme.
What I was referring to re: "Child's play" was the nature of a worst-case scenario conflict @ early stage Mars in comparison to late stage Earth. Nothing whatsoever related to how challenging it is to sustain life there in the long-term. I fully expect it to fail, I just don't expect it will be anything I'd describe as a "blood bath".
Back on Earth with the many millions of people established and living on dwindling resources and vanishing coasts, that's going to be a blood bath.