You can also check the comment history of these people to see if they are outright government trolls or brainwashed university students. Sometimes it is pretty clear.
It's not always brainwashing and indoctrination, it can also be the threat to family social standing, political scrutiny, and the ability to travel freely. If they have family or close friends that already have trouble with the state, China makes exquisite use of those factors in controlling people.
