Tony Soprano and his crew are criminals. Chances are, many Black persons they associate with will be of the crooked variety, just by the nature of their criminal connections.
And the Soprano Family members obviously don't socialize with Black people, nor do they live in neighborhoods with Black people, whether it be decent regular Black folks, successful wealthy Blacks, or criminal-type Blacks.
It's not some intentional slight on David Chase's part toward Black folks. It's just the reality of Italian gangsters that Chase has infused in these characters.