Uh, you're comparing one character to characters created separately.
At least, I hope you don't mean that there is any sort of demand to throw these different black characters into different parts of the American civil rights movement. as if these things are very successful or enlightening.
As a black comic fan I personally want something new.
The characters that were discussed, Icon, BM, etc...the time period was/is part of their back story just like WW2 is part of Capt America's back story. Even though the characters are appearing in tales that take part in contemporary times, that background informs their personalities.
I brought up the Holocaust, and Civil War ( I could have brought up the Middle Passage or the Trail of Tears or the Russian Purges) because these are time periods that are constantly visited in fiction. Some stories are good and some done poorly, but my first reaction to someone doing a movie or comic that touches on these issues wouldn't be that the creators should just get over it.
Having said that, I do agree that we could be getting a greater variety minority heroes from mainstream comics.