Chu along with a few like-minded students founded Student Politicism on May. 26, 2020 [1], just days after the Chinese Government announced the National Security Law. The group name in Chinese means "venerate studying to enlighten mind; defend citizens to ponder politics.” As the NSL silences the city’s civic society, Student Politicism became one of the few remaining local pro-democracy organizations that continued to run street booths. The core members were repeatedly arrested on suspicion of illegal assembly or sedition, and were warned of possibly breaching the NSL by the police. [2]

On Sept. 20, 2021, Chu and two other core members were arrested under the National Security Law. The police alleged them to have incited hatred against Hong Kong's government by urging people not to use the LeaveHomeSafe Covid tracking app and calling to prepare for another "revolution" through martial arts training. Four were taken to court later, charged for inciting subversion, and all denied bail. On Oct. 15, 2021, Chu was granted bail while the other three core members had their bail applications again rejected.

On Oct. 23, 2022, Chu was sentenced to 30 months in prison.