A very well-reasoned example of the Socratic method...all based on a very flawed false dichotomy. "Which hypothesis is true?" implies one is true and the other false. Both are true.
The U.S. is a nation in which white supremacy has been deeply rooted for centuries, and it is still affected by that. And it is a nation that has fundamentally changed and become a more equal opportunity place with fewer such obstacles.
Any attempt to reduce something as complicated as centuries of race relations in a diverse nation of 330 million individuals to a simple choice between two dogmatic perspectives is ludicrously limited. Such devotion to dogma is not at all progressive.