(A) Africans didn't exactly sneak in, in fact they were captured, kidnapped, and brought here in chains.
(B) Most African-Americans can trace their lineage in the United States to the early part of the 1800's if not earlier so they can't exactly go back to their family neighborhood.
(C) Blacks were the victims of a Constitutionally-approved system of legal, societal, and cultural maltreatment up until only about 50 years ago.
(A) They have, by definition, come to the United States willingly - they went to great lengths to sneak in.
(B) Most have been here in the range of a decade or less so they can return from whence they came and, one suspects, find things pretty much as they left them.
(C) If ATMs are any example (the first button you have to press tells the machine whether to proceed in English or Spanish), there are laws, rules, and customs which specifically attempt to make it easier - not more difficult - for illegal immigrants to function in the US.