Because bullying can affect people's life in many ways.
The one getting bullied might be scarred for life. Getting bullied might also lead to suicide among teenagers.
Furthermore, if students are held responsible for their actions, suicide rates will decrease.
Studies at Yale University have concluded that people who were bullied are 2 to 9 times more likely to commit suicide.
Bullying also causes the victims to skip school to avoid getting bullied. It may affect the students' education.
Bullying also triggers psychological problems resulting in anxiety or panic disorder.
If students were held responsible for bullying, suicide rates, psychological problems, and bully rates would decrease significantly.
That's all. Hope I helped.