Juliette also told Nick she didn't know that Kelly was going to be murdered. For me, the scene is a weird one. I don't know if it's really Juliette begging Nick to kill her or if it's the hexenbiest spirit taking control and daring him to murder her, so it can retaliate in justification. Adalind told Rosalie in season five that she (Rosalie) had no idea of the control a hexenbiest has over its host. Adalind's hexenbiest also broke the drug dealer's fingers without her having to say a word.
The best way to frustrate a cyberbully is to ignore him.