... is that you know who your enemies and opponents are. They will speak out against your ideas, your actions, or maybe just you on a personal level.
One reason we value these freedoms is that they help make those in power accountable. Those who disagree with particular policies or actions can say so without fear of being sanctioned, whether they were undertaken completely transparently, or undertaken with fraud and corruption.
Accountability is good for those who dissent, but is also good for those who have taken the criticized actions, because they can identify their opponents, and perhaps respond by accommodating them, or by neutralizing them.
Without freedom of speech and freedom of the press, those with the power to sanction can’t identify their opponents and enemies.
Those are my initial reactions to the Islamic terrorists who attacked the offices of Charlie Hebdo in Paris. That attack may silence some critics, but it won’t make many people view Islam more favorably. Most people view this type of violence negatively, so even people who might have been opposed to Charlie Hebdo‘s satirical depictions of Islam and Mohammed will likely be repulsed by this vigilante action.
The terrorist attack will surely create more critics of Islam than converts. It could make the critics more reluctant to speak up, but one result is that supporters of Islam will be less able to identify their opponents. It is difficult to see that attacks like this provide any benefit to Islam, and it would be better for Islam’s adherents to broadly condemn the attacks. If history is any guide, a few Muslims will speak out against them, but most will remain silent.
It is possible that many Muslims in this “silent majority” might also be repulsed by the terrorist attack, and are among those who have been intimidated against speaking up. If so, attacks like this could weaken the commitment to Islam among the faithful. But we can’t know, and they can’t know, if their policy is to use violence to silence their critics.