Further, since Haiti is cited in the thread title, it is listed high on the list of the world's most corrupt governments which is why most of its 11 million citizens are so poor and remain poor despite billions of dollars of aid being poured into that tiny nation and so little is used to make things better. When the government is corrupt and allows/sponsors corruption, the people are unlikely to enjoy much in the way of relief from abject poverty, lack of human rights, lack of much opportunity to improve their situation.
The world is full of such corrupt and poverty stricken nations and there is no way the USA can take more poor who require more than they contribute without making ourselves poorer.
Almost all more prosperous nations recognize and respect human rights and promote and encourage prosperity. Even their hardcore poor are made more comfortable in poverty. And most if not all prosperous nations are so prosperous because of the actions and example of the United States of America. We were the original role model of how a nation becomes successful and prosperous not via force but by protecting individual liberties and encouraging prosperity of the people.
Countries like Haiti, Puerto Rico, Mexico, many African nations have governments that take care of themselves and the people can be damned for so much as their government cares about them, even as they blame US for their misery.
This is by no means the whole list but the top tier of most corrupt countries as of 2015:
These Are the Most Corrupt Countries In the World | Fortune
--North Korea
--Somalia
--Afghanistan
--Sudan
--Angola
--South Sudan
--Iraq
--Lybia
--Haiti
--Guinea--Bissau
--Venezuela
It would be wonderful to help all the unfortunate people in those countries, but if we keep taking on people who require more of us than we can contribute, we become ever closer to the condition of the countries they left. And we become less and less able to be either a role model or benefactor to those who need immediate help.