A bully will try his actions out as a form of experimentation to see how far he can go without being challenged. It often starts with his/her own sense of self-importance or superiority which can be when he/she is put in a position of authority. In our world there are a few classic examples of bullying behaviour ie people being promoted to a check position who then research obscure questions with which to catch out their victims. How can the victims (who didn't know the answers) possibly report the examiner for being 'unreasonable' to, say, the Fleet office? Who is the Fleet Manager going to support? Perfect bullying country.
Eventually, enough of the abused recipients will bring this kind of behaviour to the attention of the authorities. Unfortunately it is normally too late now because the bully has been chosen by the same people who are then being asked to reconsider. Either the 'Office' does something (unusual) to restrain the bully or, ( more likely) they adopt Trafalger's misguided stance that 'every airline needs a few people like this' to maintain standards and keep us all on our toes'.What utter rubbish! Why do you think brilliant trainers like Karl V left the department? What a fantastic waste. Perfect bullying country.
We don't need bullies who surround themselves with sycophants and are fun in the bar, we need instructors who are there to teach, guide and nurture and examiners who, pretty much are similarly motivated.
Don't tolerate bullies - why should you?? Report their behaviour and get your peers to do the same.