One thing I find interesting is, as white guy, I've had very similar experiences when living in the US south. I would often be the only white guy in a store or on the street in certain areas - and felt like I didn't belong or fit in, and was treated differently. I got used to it over time, but it was still there.
I don't at all equate my experience to how difficult it can be in the US to be a black person - MOST of the places I go that aren't in certain parts of the south are mostly white (I think the US is something like 70% white?) - it's horrible the prejudices non-white, and especially black, can encounter in the US.
I DO wonder if, whenever an area is mostly one race, that if someone is not of that race encounters the same kind of thing.