Not all white people are indigenous Europeans. And if you go back far enough, the word "indigenous" becomes so vague as to be meaningless.

All people who border other people have vaguely similar cultures and frameworks. In most cases, it's impossible to define a "white" border from a "non-white" border, as borders bleed into one another.

That your child may look the same as you is no guarantee that you'll be a perfect organ donator for your child.

A model discussing abstract properties does not necessarily map into the real world https://rofasss.org/2020/05/. But, again, even if it did, white people in toto are not ethnocentric. White people include a vast admixture of cultures and ethnicities. And even if, hypothetically, white people were all one distinct culture and ethnicity, and we could map abstract properties from the model to the real world, the utilitarian nature of ethnocentrism doesn't tell us whether or not one ought to be ethnocentric. From a strictly utilitarian perspective, it may be in the best interest of an impoverished family with too many mouths to feed to kill a few of their children, but that doesn't mean that they ought to actually do so.

Calm down. White people aren't going anywhere. In a godless universe, no one deserves anything. As Dawkins put it, "In a universe of electrons and selfish genes, blind physical forces and genetic replication, some people are going to get hurt, other people are going to get lucky, and you won't find any rhyme or reason in it, nor any justice. The universe that we observe has precisely the properties we should expect if there is, at bottom, no design, no purpose, no evil, no good, nothing but pitiless indifference." In a God-full universe, there is neither Jew nor Gentile... we are all one in Christ Jesus.