First of all, in discussing bullying, a distinction needs to be made between physical bullying and kids making fun of each other.
As for the latter, it’s not something that should be a serious concern to any reasonable person. Kids have always made fun of each other, and they always will. It’s venially sinful, and teachers should correct it if they witness individual instances of it, but it’s not something to be worried about, and certainly not something to mount massive campaigns over.
The former sort of bullying (physically abusing one’s classmates) is a bit more concerning, and should warrant corporal punishment, but it again is not a matter which should warrant existential concern. Kids (particularly young boys) always have gotten into fights and always will.