If we make an analogy with the U.S., then ethnic Russians are Americans who are descendants of migrants, while ethnic non-Russians are natives.
The difference is that in the U.S. there are racial distinctions between natives and non-natives. Whereas in Russia natives can also be of European appearance. Nevertheless, they have separate languages and sometimes a different religion and culture.

Well, I don't see anything wrong here. The map shows the percentage of Russia's population, which self-idenify themselves as ethnic Russians regardless of their origin.

It's kinda complicated. Some of them lack resources or have bad geography. This is how they were saved from Russian mass migration and are able to keep their ethnic identity. Regions like Chechnya, Dagestan or Tuva are heavily donated by the federal government.

Other regions are reach of resources and have good geography, but flooded by ethnic Russians. Ethnic minorities there are well off but suffer from assimilation. Their languages and culture are dying out.

It's a hard choice. Either you are reach, but everything you love is disappearing, or you are poor but keep going.

Isn't it about any ethnicity?