The sentence just before your quote was (with emphasis added):
"It’s still worth noting how Martin’s initial suggestion that Zimmerman had shot her son in what was simply a bad encounter that got “out of hand,” speaks to a classic response to racist crimes. "
If Zimmerman is "white" because one parent is white, then our beloved Dear Reader is also white.
If Zimmerman is "white" because one parent is white, then our beloved Dear Reader is also white.