It's generally when someone brings in anything remotely off, warranted or not; then it's okay to let loose various forms of violent fantasies towards some vague enemy.

Kids get fucked. Kill the paedo, but cut his dick off first.
Women get beaten. Rough up the husband.
Someone calls a group of people "niggers." Cut that cracker a new smile.
Mike South sees his lala land image of porn getting taken apart. The comedians behind the disturbance have to leave porn forever.

So boring.