Since the shooting happened about 15 miles from me, as the crow flies, I saw lots of reports on it, including pictures of the victim as soon as they had one.

It is simply a fact that many guards at local museums ARE black...which made the shooter's 'hate' easier to manage. I have no idea what he'd have done if he encountered 2 white guards. They say he took 2 steps inside, lowered his rifle, and began shooting. Maybe he had scouted the museum earlier...*shrug*. He certainly knew he wouldn't get far with a rifle, and had to do whatever he did quickly. They say he lad lists of other buildings in his car...perhaps he just chose this museum as a symbolic place....if he survives, we may find out.
The real issue is: with this man's history, and the vitriolic posts on web sites, WHY was he not watched and 'constrained' better? I know...too many to follow. still.............