That's only Simpson's paradox if black people in the US are living longer than black people in other first-world countries. If what's actually happening is that

That's only Simpson's paradox if black people in the US are living longer than black people in other first-world countries. If what's actually happening is that the US has more black people and they're not living as long as their counterparts in (say) Finland or Austria, that's a different matter. (Though the effect that drives Simpson's paradox could still be the largest cause of the US's not-so-good performance in overall life expectancy.)