If i had to guess,, It's because you do care if the guy winds up being a pin cushion for a few hundred pieces of plastic shot out at the speed of a rifle round.  Or,, it happens to a child, family member, or someone just walking into the shop.  Totally innocent bystander.

Unfortunately,,, it is just like someone who is or has talked about suicide and is very depressed.

You can talk, explain there is a better alternative, life is more important, other people would be emotionally crushed etc.. You can talk till you are blue in the face. But the reality is..

If someone is truly intent on committing suicide they will find a way. In this instance it is the same as Russian roulete..   He can pull that trigger for 15 years and walk away laughing. However at 15 years 2 days he may pull the trigger and there WILL be a loaded round in the chamber.

You took the lead,, a lot of people were right behind you and still didn't matter. He's still laughing and pulling the trigger.  He may keep hitting empty cylinders or he will be in the News. 

Ultimately it is his choice.  No matter it may well kill him,, still his choice.

Everyday people do dumb things and pay the price for their decisions.

(insert smiley face here)