I think they are people, who suffer from the less of self confidence. And through their behaviour they strive to sure others in their power. I suppose all people had an experience of contacting with bullies. Some people in the war with them, others capitulate. I don't think that the second variant is the right way of solving the problem.
Bullies believe only in strength.
So if you are alone, with no one to support you, it's better to try to avoid the conflict, because bullies don't deny violence and even can use it. In fact, it's better to fight with bullies with the help of words. Once I had an experience of dealing with bullies. And I was embarrassed, I didn't know what to do. I changed a school, so I was in the absolutely new grade, where I didn't know anybody.