A guy with black friends and pix of him with his black friends is not going to go kill blacks because they are black.
But he might well kill them if he hates Christians. Or is a Muslim. Or Gay. But whatever he is, it isn’t a racist.
I'm going with the "Gay" angle. That train conductor that derailed that train is "Gay". That German airline pilot that crashed his plane into the ground was reported to also be "Gay". Most of the Serial killers in our history were "Gay".
I'm betting it's the normal expression of homosexual murderous rage at people who say their lifestyle is sinful.