At least in the US, it is common for educators to teach children ages 5-17 why bullying is wrong, generally through short lesson units or campaigns. Even at the university level, it is common for universities, schools or students' unions to host trainings, events and workshops that aim to promote respect or getting along with other students. While the motivation behind these programs comes from a good place, these programs often fail to prevent long-term bullying and conflict between students - largely because they get so much about the issue wrong.
The primary mistake that anti-bullying education makes is that it frames bullying as targeted, person-to-person acts such as shoving students into lockers, creating cliques with specific rules members must follow or stealing lunch money. While all of these things do count as bullying, they aren't terribly common in modern schools. The common image of a bunch of students calling a smaller students mean names is rarely actually seen, so when students are prevented with exaggerated, near-comical images of what 'bullying' is supposed to be, they assume that they can't be guilty of it.
In reality, bullying is largely a more subtle process of social exclusion. Indeed, there are many students who are wholeheartedly socially isolated, for reasons far more insidious and complex than the superficial adolescent politics of who has the newest clothes. For instance, many students would think it wrong to call a friend mean names for being short, but might make misogynistic or racist comments about a group of students as a whole. After all, prejudice has long been part of the status quo, and it's not as if they are personally teasing someone in a cruel way as students in the anti-bullying films do, so it must be fine.
The way that educational institutions treat the issue as a whole doesn't help matters either. Anti-bullying education is often relegated to an assembly, an awareness week or a few lessons at the beginning of the year, rather than treated as a standard policy. Teachers who are more than happy to tell students to not make fun of each other's socioeconomic status often completely ignore the fact that students with less money are completely excluded from the worldviews of others, such as by being automatically assumed to be less intelligent or hardworking than students with more. Schools tend to further reinforce these views by only including the perspectives of certain demographics in curricula and refusing to take on any real-world social, political or environmental injustices, allowing students to maintain prejudiced views while believing that they can't be guilty of bullying because they aren't starting physical fights or targeting smaller, less physically strong students for harrassment. Prejudice can be even more subtle--a student who has received simple messages about not making fun of another student's anxiety may still be uncomfortable if said student speaks up in a frank way about how the prevailing culture treats them or displays symptoms that others might consider 'strange'.
If asked, I would never say that I was bullied growing up. I was never hit, my possessions were never stolen, a group of other girls didn't follow me around saying I was wearing the wrong colors to be friends with them and I was never called names for wearing glasses. But the smaller signs, people laughing when I was angry, people I didn't know pretending they wanted to be my best friend or ask me out as a joke and the constant dismissal of my perspectives by adults sent a clear message: you and your views don't mean anything and you just shouldn't be like this. It didn't make me feel worthless or wrong; in fact, it just made me double down on my critical views--what was wrong with my community that responsible adults who knew how the world worked weren't questioning the youthful ignorance of young people who clearly didn't know better and were as capable as anyone else of learning right and wrong? Although I certainly don't blame children--whether current children or those who were children when I was also a child--for my deep social unease, I can't help but think that adults in my life could have done far more to model and promote a more inclusive, open-minded and forward-thinking culture that allows for uncomfortable conversations and facilitates greater community change when necessary.