Hong Kong's activists defend universal principles rather than fighting for one group and against another.

However, there are rumors they might plan violence in their next protest.

Perhaps this is a misunderstanding. Perhaps the activists only recognize that the thugs may respond with violence to their next nonviolent protest.

Given that the puppet government is planning to send them to Chinese prisons, I could not blame morally them for fighting back with violence. But that would be foolish and self-defeating. Violent protests play into the hands of the authoritarians.