Samson, http://www.city-data.com/city/Oakland-California.html Crime and Poverty appears to be a bit of a problem in Oakland. Don't know why. There are 564 sex offenders who live there also. This is according to 2013 data.
I wouldn't say racist, she justified her reasons for why she thinks he isn't a resident. If she just said he was black, then sure that would be an ignorant assumption, but judging by the description and it happened (assuming from Mikey's post) in oakland; I wouldn't call it racism.