It is quite an inconvenient hypothesis. Unfortunately I have some weak data that leads the question to persist and no strong evidence against it. I see no reason why it can be dismissed.
Time and time again, we prove those hypothesis wrong. As countries develop and equality is prioritized, we see more and more differences disappear.
Ultimately, I have no reason to believe we have achieved the apex of development or equality. Systemic racism is real, because racism doesn't just disappear. We implemented integration just a few decades ago in a lot of communities, and that disconnect and resentment that built doesn't just - poof! - disappear. It continues on and manifests in less opportunities for education, more drugs in communities, and a lot of second order effects that transcend generations.
We even still see black populations today distributed as we saw them during slavery. And that was 150 years ago. These things don't get solved, they just get better, a little bit at a time over very long periods of time.
I dismiss the hypothesis because we have already dismissed the hypothesis more times than we can count. And, I have no reason to believe this time it's different.
If even sovereign, nord-level equal in income, relatively well off black nations have US-black level infant mortality then it's not really my place to tell them to be more like the white man and do something that drops it but has god knows what other unintended consequences. Maybe they benefit in some other way. I have no idea.
I hope someday society can see your plan of less interventionism is the more correct one.