A cautious posting about ethnic/cultural differences

This weekend I’m moving from the ethnically-diverse city of East Palo Alto, to nearby Mountain View. One observation I have based on living in an area with a large African-American community is that there are more people willing to strike up a conversation with a complete stranger, as in talking to me, than I’d otherwise expect.

I just wonder how it’s perceived from the other side of the racial divide – do African Americans think the reason why white people don’t strike up conversations with them is racism? Someone who is African-American might notice the same difference I've noticed, but not know whether white people are more likely to start conversations among themselves. Racism is always a possible reason for how people treat other ethnic groups, but the other reason could just be cultural differences.