I don't really care why someone committed suicide at a gun range. Everyone has problems, but it is WRONG to make your problems someone else's. I look at it this way, at the very least, the guy was acting in a very reckless manner with a gun, violating a whole host of range rules. Now, if someone did that at a range you were shooting at, just didn't actually shoot himself, how ticked off would you be at that person. Why do we give some idiot a pass on reckless behavior just because he actually killed himself?
If we stop feeling sorry for people who do this kind of thing and talk in terms of their stupidity, selfishness, reckless behavior, and total disregard for gun safety and the people around them, then just maybe the next person will think "Hm, will people think I'm a complete butt-head for blowing my brains out at a gun range?"?