No flacaltenn it is not anecdotal. If I was like your racist buddies, I would make a thread and put up 9-10 stories like this every day. But I don't have the time to waste doing that. And if I did that, you'd move or close the thread.
You are looking for an excuse. It doesn't matter if these guys knew each other, it doesn't matter what kind of grade the school got for diversity, this is white on white crime and had 3 blacks done this you wou;d not be making excuses or doing mental gymnastics trying to find a way to dfferentiate how the crime was done.