No government wants or enjoys criticism, even as they all lie and say they welcome it. Further, everybody knows these two humble truths.
It is only when a government decides it will not allow political criticism that a state of tyranny exists. The emphasis is on political.
For example, a critic (with good reason) charges the government with theft over some new tax policy. The government moves to shut the critic up, perhaps by arresting him. A standard, everyday regime suppression technique.