What kind of white supremacist country would have let a black man named Barack Obama anywhere near presidency?

The fact that the US is failing at repressing black people doesn’t mean the US isn’t inherently white supremacist - just like the fact that the US was defeated in Vietnam and Afghanistan doesn’t mean the US isn’t fundamentally a colonialist empire. In both cases, the answer is in the affirmative - the US is fundamentally white supremacist and it is fundamentally colonialist. The fact that it has failed at both on many occasions doesn’t negate the truth of that. Apartheid-South Africa was similarly fundamentally white supremacist - the fact that it failed to repress it’s black population doesn’t suddenly mean that Apartheid-South Africa wasn’t fundamentally white supremacist.

You seem to believe that the fact that the long struggle black (and other people) have had to wage in the US simply to be seen as human (somehow) “proves” that the US isn’t fundamentally white supremacist while completely ignoring the blatantly obvious reason why such struggles was necessary in the first damn place and are still ongoing.