Seeing I'm not African-American, you know the dinner table talk in that community far better than I will ever know. I do dispute the notion that Obama did nothing for the African-American community. He got a lot of people who didn't have health insurance covered. That caused problems in other areas, but that shouldn't be overlooked. He launched My Brother's Keeper, which was then roundly criticized by the more liberal elements in the black community as being paternalistic. Several times he spoke about how young black men needed to act more responsibly, only to be ridiculed for being "too white." He pardoned a number of African-American prisoners convicted of non-violent drug offenses. After the various police shootings, he supported local law enforcement officials while explaining that he understood the feeling in the black community and managed to tick off both sides.
As per stop-and-frisk, I didn't realize Obama was Police Commissioner in Chief. Those policies are all developed and implemented locally.