Contrary to popular belief, America's immigration laws were not put in place for anyone and everyone to become American citizens. It has stipulations that must be met by all applicants, just ask those who came through Ellis Island.
If certain requirements are met, those applying for citizen are granted it. It is not a one way street designed just for the benefit of those seeking citizenship. America must receive something in return for that citizenship like people who can speak, read and write English and offer a skill or semi-skill that helps America grow as a nation.
If we minimize those requirements or eliminate them completely, allowing everyone from third world countries who want to come to America to do so and who have nothing to offer in return for American citizenship but more poverty and a drain on our social services, then America will quickly become just like the poverty stricken places the immigrants left.
More @ AL