Answer:
The significance of using the lines "I am Malala" in their protests shows their solidarity with the injured activist. They are openly declaring that they are not afraid of the Taliban and instead of being silenced, the voice of Malala will grow bigger and stronger.
Step-by-step explanation:
Malala Yousafzai is a Pakistani teenage girl who was shot by the Taliban for her belief in and help in spreading awareness of the need for educating girls. In a male-dominated society and with the belief that Islam dictates women be at home, the Taliban believes that Malala was a hindrance to their society and decided to target her to stop anyone else from campaigning for girls’ education.
While she was shot in the head, and taken to a hospital in Birmingham, UK, protests began in her name, some calling for the Pakistan government to act and some showing support for her cause. Some protesters held the sign "I am Malala" and scaled the streets to get their voices heard.
I presenting themselves as Malala, these protesters are showing their support for the injured girl. They are declaring that they are all "Malalas", a single voice, a single entity. And through this, they seem to be declaring that they are standing with her and that they are not afraid to protest and demand what is theirs. They are openly advocating what Malala had done and worked for, and that the Taliban hadn't silenced the little girl. Rather, she has found a voice much stronger and greater.