It’s not just one bishop. The official policy, not just of the Catholic Church but that of most Christian sects, seems to be that Western nations have an obligation toward all less fortunate people. The “thinking” is that we must follow Christ’s compassionate example: Feed the hungry, heal the sick, clothe the naked. They never remember that Jesus never said we must steal from those that have and give it to those who don’t. Of course He also said that it was harder for a camel to pass through the eye of a needle than for a rich man to enter heaven. So maybe the socialist Christian do-gooders have the rich man’s best interests at heart—By stealing their money and giving it to the poor, they’re just trying to help the rich get into heaven.
I do not believe that valid Catholic doctrine dictates that the people of one country are OBLIGED to take care of people from another country.
The more fortunate have an obligation to look after the less fortunate, As An Expression of their love for God and all of His children.
This is entirely different from denying that a nation cannot have borders.