Education is such an important tool in the advancement of countries and societies out of both economic poverty and backwards religious-morality. Sponsoring children can be beneficial in allowing poor countries to become larger parts of the world stage, but its not a simple process - the educated must return home, and not stay in the west, so that they can truly help their countrypeople.
Some might say that it is somewhat exploitative, but I think that as long as these programs are doing what they purport to be doing (actually helping the children, providing for them, without the money going more to the corporation or etc.) then they are having a positive impact on the children.
While America is being made Great Again, we still should continue to focus on fixing our country and sponsoring low income children that are highly intelligent in our own country. It isn't always America's job to police the world. Even if the people sponsored come to the west, they probably won't return back to their home country, not allowing it to develop.