As far I have I read the poem, it's about the mistreatment because of "skin colour differences"
Explanation:
So, The primary concept that Hughes is trying to get across is that there exists prejudice and fanaticism, however you want to transcend this, and treat each other with decency and equity. The speaker indicates his expectation for America with the aid of pronouncing that one day, the sector will well known him, and lament often persecuting his race.
He is saying that black people are also a part of America, and that soon he'll be able to sit at the same table as whites, and be seen as the same as them.
