But the problem is that the "liberation" of 2+ billion people from responsible government (Britain, France, Germany, Portugal, Turkey, Afrikaners and, to a degree,the USA) has created a condition of permanent and worsening distress among the 75% of the world population which is incapable of self-government.
This "moral duty" can only be carried out by permitting massive resettlements (i.e., national suicide) or colonialism.
I think the author makes the same point, that help can be only extended marginally.
I actually would say that the West would have a moral duty to recolonize some parts of the world if the moods and circumstances change and we are invited to come and govern. At this point it sounds silly and impossible, and contrary to political correctness.