Maybe there was no official policy previously and the unofficial policy was a combination of “patriotic 
user complaints” and “automated scanning”.
It seems likely that user posting will become untenable for many sites in China, due to the requirement to hire
a review and editing team suitable for the scale of services
That just doesn’t seem viable for many smaller companies. In addition, there is the small risk of corruption of the review team from constant exposure to dissident comment.
It is well known that people living under an authoritarian regime develop their own way of speaking about things without actually saying it. It is possible that this language has become too subtle for the Chinese government’s AI - because otherwise surely automating this process is the way to go.
One interesting word that appears in that article is “edit” - as in “review and edit”. In many democratic contexts, “edit” would be seen as unacceptable i.e. take down unacceptable content if you must but don’t edit it to put words into the mouth of the author or to change the meaning or to change the posted text at all. I wonder how “edit” is to be interpreted in this context. Maybe lost in translation.