What people have to understand
Being called a slut is not the point.
Being cyberbullied is not the point.
"Choosing" not to let someone have power over you is not the point.
Lindsey (unfortunately) had the power of popularity. When she called Taylor a name, 50 people joined in on her side and ALSO called Taylor names. When Taylor called Lindsey a bitch only one person took her side.
People were afraid of Lindsey. It's that simple. Nobody wants to be the target of a 50-person attack. That's why Cheyenne stopped hanging with Taylor.
Taylor couldn't just choose not to let Lindsey have power over her. Lindsey had the power to peer-pressure her friends away. It's as simple as that. You could argue that Cheyenne must not have been a good friend if her friendship didn't mean enough to stand up to the peer pressure, and you might be right, but that's not the point.
I saw this all the time in my own high school. A verbal bully would make fun of some's physical defect, or mother's health problem blah blah blah and everyone standing there would laugh along. *I* think it was because they were afraid that if they said "Hey, that's not funny" that the verbal bully would turn his taunting wrath on him. Cowardice. Hypocrisy.
I have more to type but I'll have to finish it up later - hope this much made sense.