I have zero issue with marriages that happen to be same race. Hopefully, they respect others of different races, since tolerance is critical in the early stages of integration where people are not integrated.
But it seems racist to exclude someone from your circle simply because they have a different skin color. Instead, progressing to social integration is the natural step since good people exist in among all ethnicities and races, so why exclude them? You are the one that seems to struggle with the idea that eventually biological integration is the natural last phase. No need to force it, it happens on its own over time...as in generations.
Biracial Americans including Obama and Kamala Harris have held the post of President or Vice President during 12 of the last 16 years and that they reflect the "tip of the spear" regarding the changes going on in America. Imagine what other demographic that is so small as a percentage of the total population have held such senior political leadership positions in American history.
Furthermore, why you think their positions reinforced the hierarchical system is beyond me. Neither were born rich. So, they were not part of the "upper class", nor did they benefit from racial privilege. Both Obama and Harris claim to have experienced discrimination, but that discrimination did not prevent them from reaching the top.
I don't like their politics, but their ethnicity highlights that mixed race people often have the unique ability to transcend one race and embrace all of them.
As to future, the simple math says you are wrong, like a snowball rolling down a hill, integration is happening. We have reached the point of no return in several states like California, it is easy to see the ethnic melting pot of the past now blending the different races.
As for African Americans, they are already much farther down this path than whites.
"The average African-American genome, for example, is 73.2% African, 24% European, and 0.8% Native American, the team reports online today in The American Journal of Human Genetics."
In other words, the average black man or woman today is mixed race but may not realize it. How do you think they can "unmix" their genes?
Why am I focused on breaking down the barriers and promoting integration...
Because my family is mixed race, I see their ability to mix easily with people of all races, I realize how important it is in a "country of immigrants" to promote integration at all levels... we have enough enemies in the world, we don't need to each other as enemies.
Secondly, history supports my hope. Native Americans were so ethnically focused they could not unite against Europeans in spite of their early advantage in numbers. The same happened in Africa. Everywhere white people went they were able to use ethnic and racial division to divide their enemies and conquer. Anyone who has ever played on a team, understands how important it is for a team to be a team and not separate identities.