All multiracial and multicultural societies break into tribes which are, to varying degrees, antithetical to each other.
In the Middle East the Sunni and Shia are the same people genetically, but break into tribes based on religion.
Pakistanis and Indians are largely the same people but a religious divide caused two nations to be formed. Ditto for the even more recent Sudan and South Sudan.
Zimbabwe and South African politics and policies deeply involve a black vs. white dynamic.
The riots in Europe over the past several decades (minus the austerity riots) have almost always been ethnic minorities railing against the ethic majority.
American riots of the past half century have almost always been black riots railing against a perceived racist white power structure.
Even in nations where there is no open conflict, racial or religious groups often vote in blocs against each other.
Diversity is not strength. Diversity always leads to a tension that must be massaged so that it doesn't lead to open conflict.
I don’t necessarily disagree with you, but what I allude to involves more than race. In our country (and others perhaps), men and women, rich and poor, urban and rural, gay and straight so-on and so forth have been pitted against each other by political interests. Look at the hatred developing between American whites of different ideologies or political views. Politicians don’t call these groups ‘tribes’ however. They call them voting blocs, but the principle is the same. You say that mutual antipathies of race and ethnicity are a natural occurrence and you’re probably right, but I believe that most of the polarization in our society presently, including race, is brought about and when not...intensified by a self-serving political class that benefits from keeping us at each others throats.
Diversity is a strength is one of the biggest lies ever told and what is ultimately leading to the destruction of the US.