It mentioned that the groups were closed. It also showed how the documents were labeled as internal sensitive information.
Sure the data no doubt had more than one purpose, but if all they were concerned about were bugs in the platform they could easily have a bug reporting box like thousands of other software platforms. It’s not as if a company like Amazon can’t figure out how to improve a service without religiously monitoring a closed fb group.
Combined with the job posting for analysts to stop labor organizing/protests I think their ultimate motivation is pretty clear.