Ruling is all about balance and drawing lines. Why is alcohol and tobacco banned for people under 18? Why are heroine and cocaine banned? Aren't these two cases examples of liberties that the government is cutting?
The government draws a line when the age to vote is 18, or when the age to drink is 18, or when it prevents you from owning an ak-47. There is no escaping drawing lines, it is inherent to life. Even when not seemingly drawing any line, you are just drawing a line somewhere due to inertia, a sort of implicit default.
Some lines are popular, such as the drinking age, others are impopular, such as tax rates, but both are necessary.
A society drunk on liberty is an evil too, as ancient philosophers already exposed, as there is no balance.
The role of the rulers of a people is not only to enforce the collective will of the people, but to go beyond it to the position of a leader. No one wants to pay taxes or a tax hike, but if there are no taxes, a state cannot be run. Here, the leaders are going beyond the collective will to protect the collective itself.
There are also plenty of cases where the collective is misguided, such in the case of the entertainment industry (and I'm including trash and sloppy TV and online content here), which is idiotizing society. Should people be throwing themselves into an abyss of hedonism instead of following the value of temperance and seeking wisdom? Yes, but many do not. The state of our current societies reflect our current values. "Got what I voted for", right? Disfruten lo votado, as we say in Spanish.
Here is where the imperative of the leader to do what is good and right is most obvious. The leaders are supposed to be the best among us, and while they often are not (again, a reflection of the values of society), this legitimizes them to make unpopular choices, up to a certain degree. The degree of power to invest in a leader is also a line that the collective draws. (As a note to this, bad leaders like Trump are both a reflection of the values of society, and the result of good leaders failing to do what is right and good. There are other factors, but these are the most important ones.)
When governments decide to ban social media (which is different from censorship, if only the medium is banned and not the message), a line is being drawed, and in my opinion, it is a good line to draw.