Every society that came to america poor is no longer poor,

Latin Americans? Their average income is barely above black americans when compared with asian, jewish, or even white americans.

You cannot play the racism card because there was racism against all non white races and even white ethnicities like the Irish.

There's a difference between everyone suffered racism and everyone was as poor, as uneducated and as disenfranchised when they got to this country. The answer is no other race has been as poorly treated and down trodden as black americans, and it's not even close. Again, Irish, Chinese, and Jewish people could all vote before black people. As an example there was a time when the chinese could not yet be citizens, but even at that time they were allowed to conduct business and ride in train cars with white people, yet black citizens could not:

"There is a race so different from our own that we do not permit those belonging to it to become citizens of the United States. Persons belonging to it are, with few exceptions, absolutely excluded from our country. I allude to the Chinese race. But, by the statute in question, a Chinaman can ride in the same passenger coach with white citizens of the United States, while citizens of the black race in Louisiana, many of whom, perhaps, risked their lives for the preservation of the Union... and who have all the legal rights that belong to white citizens, are yet declared to be criminals, liable to imprisonment, if they ride in a public coach occupied by citizens of the white race"

Everyone suffered some racism, but racism against black people was much more pervasive, longer, and more extreme. As an example:

Most lynchings from the late 19th through the early 20th century were of African Americans in the South.[3][20] Other victims included white immigrants, and, in the Southwest, Latinos. Of the 468 lynching victims in Texas between 1885 and 1942, 339 were black, 77 white, 53 Hispanic, and 1 Indian.[21]

Violence and exclusion of black people from the majority of society was much much higher than of the chinese, irish, or jews. If you think otherwise, you're just working off bad information buddy.