I'm sorry, what were you expecting to happen? That we'd all post, 'oooh that's too bad' and then put it out of our heads?
I'm actually happy that guy posted that odd comment, because it illustrates how connected everything actually IS, and how much work remains to be done before we can coexist peacefully in this big, diverse, country where some people do feel disenfranchised enough to consider robbing their neighbor, and others are aware on some level of the desperation of those people and as a result, fear them enough to KILL.
Sometimes you have to discuss things that are hard to talk about in order to bring positive change to your community.