I've lived in an area while saving for a house that's probably majority black in and around the block I live in (it seems that way but I'm not sure), but the surrounding area has a large asian sprawl, a latino neighborhood, and then some mostly white suburbs dotted all about. This is close to what could be considered "the South" so the black areas are longstanding. Thanks to a long-standing military presence much of the population is diverse like this and transient. So we get people from all over, sometimes briefly.
I haven't noticed this behavior in my many black neighbors. I have a feeling it's regional. I leave things out on my porch all of the time. We're friendly in passing. For the most part they're courteous, though since apartment living is kind of new to me there are things they all do that seems rude to me, but maybe that's just apartment life. Sometimes one comes through who is painfully trying to project "the thug life", but I grew up an actual poor, rough area, and their tough facades and glares have no effect. The worst thing I saw was at 4 AM someone from another neighborhood was drunk and walking down the street openly with a gun. I think was some altercation and he was returning - I only got fuzzy details later.
Anyways, there are a few negative things I've noticed:
I hope all of this doesn't make me seem racist. Just observations having lived in this area for a few years.