Speaking as someone who has gotten stabbed over a fucking dispute on a bar tab, I can tell you that getting stabbed once is enough to make you tuck tail and get away. When you stab someone, you're showing the intention of taking their life. Ending it. Permanent Vacation, whatever you want to call it.
The kid may have started off in the realm of self-defense, but this is the problem with bullying. Eventually, if the bully is successful, they will succeed in making the victim feel isolated from any course of action, or any way to find help. I do not agree at all with the kid's overreaction. There's a mighty big fucking difference from getting beat on by bullies and having them try to end your life. The kid ended another child's life. It's gone now. Finished. That person has ceased to exist and will not be coming back, ever. You can say he was a shitty person for bullying, but what are you, save for a keyboard warrior who doesn't truly understand the severity of these events? Lives have been ruined over this. Many lives. But of course the keyboard warriors think all is fine and good simply because they got the chance to vicariously cheer for the little guy who got stepped on. It doesn't justify murder, no matter how badly you want to celebrate the demise of a child.
And that's the biggest disappointment about this thread. People are actively celebrating the murder of a kid. A kid who obviously needed help. It's one thing to say "Yeah, the victim had no choice but to defend himself" and another entirely to sit there and gloat over how another person's life has been unduly cut short. It's disgusting to witness, and I am absolutely ashamed of the quality of person that festers on this site.
Who would have guessed that bullying would be a touchy subject on this video game forum.