A few k stars on Twitter is hardly blowing up. More plausible explanation: journalist was using WeChat in “creative” ways looking for a story (even admitted to “probing”, though didn’t mention anything else she probed), got account closed after a while, attributed it to the last action, although that was not actually the cause (could be a combination of various activities).

This could also have been a manual job :)

Someone is probably watching closely what this reporter is doing.

Or her account was flagged for any number of reasons when a user changes a password on any service.

I've seen worse user experiences.

But yeah lets just go with the passwords are in plaintext and she's a journalist beijing doesn't like as the only possible outcome. Thats the explanation I'm going to go with when Facebook security reviews blindside my new accounts and close it unilaterally.