Are you feigning ignorance here or did you actually think the original comment's repeated pejorative of 'worthless thugs' was talking about white people?
Not in San Francisco, but there are plenty of white "worthless thugs." See under: http://en.wikipedia.org/wiki/Chav. The American equivalent starts around 80 miles east of here and doesn't let up until Westchester County - I exaggerate, slightly. See under: "Winter's Bone."
Except people don't casually malign them as "thugs". "Rednecks", maybe. In the context of the original comment, there was definitely a racial component and liberal use of the word "worthless".
You can dispute whether that's racist, maybe, but being shocked at the suggestion? It quite clearly has a racial element.