Is this the only way that situation gets resolve or are there any alternatives? Why is the kid a bully? Why does he feel the need to copy homework? Maybe the classmates should group together and seriously injury the bully first, would they be in the right if they did so? How do you know the bully will actually harm the kid and doesn't just want to scare him?
You can make any situation a simple good-evil answer by drawing arbitrary boundaries around the situation. The propaganda this thread is mentioning enforces those boundaries and potentially prevents people from discussing the real underlying problems. Doesn't mean the outcome or conclusion is any different.