People are also unwilling to express agreement because they know, and fear, group consensus and the pressure to fit in. Those usually lead to groupspeak and groupthink.

Given that one of the primary messages of the local Powers That Be is that other people's evaluations should be a factor in your own - that other people's conclusions should be considered as evidence when you try to conclude - and that's incompatible with effective rationality, as well as the techniques needed to prevent self-reinforcing mob consensus.