SO why is it "not bullying"? Surely it is both?
I say its just plain abuse/assault.
My line of bullying and whats more/less extreme may and probably does differ from yours quite a bit.
For me, bullying is simply name calling, shoving and generally annoying someone on purpose with the intention of upsetting or pissing them off, using any aspects of a persons physical and mental structure as a weapon against them. I think the bullying line gets crossed once the victim is being stalked and has their home targetted.
A scenario where what your experience was could be different; There are 2 gangs [x] and [z], now these gangs hate each other and have a tendency to fit using sharp weapons and/or any damaging thing at their disposal. Now one day gang [x] catch one of gang [z]'s members, chase him, batter him and before leaving they slash his face.
Would you say this is bullying or just plain assault.