If not done officially, but everyone knows that by being a political activist you can get foreign citizenship, you have just motivated people to fight!
Edit: dual-citizenship for an activist puts a China into a catch-22. China can’t complain if the optics are that the activist is just a normal person asserting their rights. If China does attack the activist, then the other country can rightfully argue that the activist is a political refugee, and as a citizen of their country they can defend them properly.