What exactly did Fang Fang write? The West has a habit of picking up nobodies and portraying them as some kind of celebrity.
Fang Fang did not have any legal action against her despite her writings being highly critical of the Chinese government's coronavirus handling and also having had far more impact than anything Zhang wrote. This is why the Zhang's case is curious. The western media is presenting the Zhang case as the Chinese government silencing critics of its coronavirus handling, but if that were the case, Fang Fang should have been arrested too or at the minimum silenced. Instead, Fang Fang is still active on her weibo and her Wuhan Diary is widely circulated. So something else must be going on with the Zhang Zhan case.