Those were conscious biases though. Most people in our society try very hard to avoid even unconscious bias, often by being consciously biased against minority

Those were conscious biases though. Most people in our society try very hard to avoid even unconscious bias, often by being consciously biased against minority groups (this might range from small acts of kindness toward a minority group to nonprofits that serve minority groups to corporate inclusivity policies to government programs and affirmative action policies). Given all that, I have a hard time believing bias plays a large role in explaining disparities.