Do I get weird looks because I'm white or because she's black?

My girlfriend is black and lives in a mixed neighborhood in which no particular ethnicity dominates, but one of my favorite places to go out is in a predominantly black neighborhood in South LA. When I go there by myself I occasionally get hled on the street for being a "white boy", while the people who frequent the place are very friendly to me (and I'm almost always the only non-black person there). Yet all in all I get weird looks and sometimes even offensive comments in that neighborhood sometimes, especially when I am with my girlfriend. I'm wondering if it's because white people usually stay out of those areas (not sure if this is true, to be honest), or whether they might be offended to see a beautiful black woman hanging out with a (very) white guy. Or if there might be some other reason that I have not thought of...the way I dress, walk, etc. Any ideas?