I think that the reason why internationalist elites support Third World nationalism while opposing the nationalism of developed nations is that the nationalism of the Third World is no threat to them: no Sub-Saharan African, Arab, or Central American country will ever wield substantial military or economic power. So why not encourage their nationalism as a tool against now-emasculated western nations, whose nationalism would be potential threat to the power of international alphabet agencies and transnational corporations? And if Third World racial chauvinism can be combined with mass immigration, all the better for the elites.
The elitists know they cannot defeat nationalism by confronting it directly.
Therefor they must dilute its strength by importing millions of non-nationals to the countries in question to make it weaker and weaker until it is seen as an abomination like ‘slavery’................