Well, no one is saying that it will eliminate senseless murders altogether. I'm sure there will be some of that. As the evidence that people have already posted, it will lower it which is obviously a good thing and all we can hope for. Hell, for all we know is that it might make people be more nicer to others (in the examples you posted) knowing that there's a chance the other dude is packing (even if you are too).

BTW, "internet tough guy" is a whole different animal. There is no solution to that growing epidemic yet.