>300 Years ago, an advanced human civilization appeared in the solar system.
>They came out of a wormhole and claimed to be from 1500 years in the future.
>Turns out they came from a different future. Big whoops.
>Still, at least it confirmed Multiverse Theory.
>Created a flying continent, colonized the many planets in the solar system- including moons- and then started turning all of Earth into a resource extraction site.
>Allowed lots of immigrants from iron age civilizations to do work they could totally automate, but don't want to because it would be expensive.
>300 years later, in modern times, only around 10% of the population are descendants of the original Downstreamers. 10% more are mixed race. The other 80% are immigrants with no citizenship.

The immigrants have started to wonder why they don't get to vote despite running the economy, and are screaming for democracy. The Downstreamers are already democratic, but they don't want to open citizenship to normies.

Important thing to note is that the Downstreamers are genetically augmented. They are genuinely just physically superior. They don't get sick or old, they are stronger and fitter than we'll ever be, they have mental enhancements that let them communicate with machines etc.

They have basically decided to leave the solar system and colonize others. They're not cruel enough to just kill the normies, but neither are they tolerant enough to coexist. It's the best compromise they can give.

They also plan to create an entirely robotic workforce in their new system to avoid such problems happening again.