Bullying is a natural instinct when one or several members of the tribe engage in behavior that goes against the tribe's way of doing things, which endangers the cohesion and the probability of survival of the group. Bullying those individuals allow them to return to the herd.
The issue nowadays is that we are confronted with a lot (a lot) of people and our bullying instinct is out of control because there are many people doing many antisocial and dangerous things around, so the feeling never goes away.
Bullying is a good tool, but you shouldn't consider everyone you see members of the tribe that need to be corrected. Observe and laugh from afar.