This goes on too. Concentration camps for asian-americans, constant abuses of Native American populations, the constant harassment of immigrant cultures- none of this was imported with immigrants, it's the product of a society they desperately wants to remain homogenous
It's not just because it stereotypes individuals, groups them, and judges them based on involuntary criteria (skin color). There is a rich history of American white culture absolutely opposed to racism. For example, white Quakers fought slavery since the 17th century, often at personal cost [1]. Countless white people died in the Civil War over the issue of slavery.
So I reject the entire idea of a 'ruling race'. I guess 'ruling class' is technically more fluid, but people often have notions of class foisted on them, including here, so it's not necessarily any better.
[1] https://en.wikipedia.org/wiki/Quakers_in_the_Abolition_Movem...
You basic argument is that immigrant culture has no effect on violence but the culture of another group(the white people) does. Ok, so in that case, nations completely ruled by the culture the immigrants comes from, must inherently be free of major violence. Hmmm does that sound correct.
If anything, the west post world war 2 bred a new culture that gave birth to true liberty. The democracies formed in this period shaped the freedoms we have today, and pushed for human rights and equality. There is still progress to make, but targeting groups of people is no solution.
Btw I am Indian, and if you want to argue that ruling whites are a source of major violence, just go and read the history of India from 1000-1800. No white people, lots and lots of violence. All races are the same.