This is only true in the context of selective immigration policy. If your immigration standards are high, you'll get exceptional people from everywhere. The US currently has no standards whatsoever (actually, the incentives are to discourage high skilled, law-abiding people from migrating) so that observation will quickly be obsolete.
It's still a gamble though. You regularly hear about some immigrant doctor or other professional being busted for fake credentials. Personally I don't take the risk.
I will add a caveat that doctors actually from Africa are pretty solid in my experience.
This is only true in the context of selective immigration policy. If your immigration standards are high, you'll get exceptional people from everywhere. The US currently has no standards whatsoever (actually, the incentives are to discourage high skilled, law-abiding people from migrating) so that observation will quickly be obsolete.
It's still a gamble though. You regularly hear about some immigrant doctor or other professional being busted for fake credentials. Personally I don't take the risk.