I think these are all excellent observations, but I have to add that this isn't the ONLY reason people get bullied. I was a minority in my school, and when the bullying (physical and verbal) started, it was 100% due to this fact.

However, I eventually developed the body language of a victim. That DID serve as giant sign for bullies to proceed. And once I was marked as a victim, I became a convenient punching bag for any kid that needed to get some violence out of their system.

One day, I decided that I was going to kill the next person who hit me. I never said it aloud, but it must have been clear in my body language. The bullying abruptly stopped! (Good thing, too, eh?