This following quote from Thomas Jefferson is a very special one:
"If nature has made any one thing less susceptible than all others of exclusive property, it is the action of the thinking power called an idea, which an individual may exclusively possess as long as he keeps it to himself; but the moment it is divulged, it forces itself into the possession of everyone, and the receiver cannot dispossess himself of it.
Its peculiar character, too, is that no one possesses the less, because every other possesses the whole of it. He who receives an idea from me, receives instruction himself without lessening mine; as he who lights his taper at mine, receives light without darkening me.
That ideas should freely spread from one to another over the globe, for the moral and mutual instruction of man, and improvement of his condition, seems to have been peculiarly and benevolently designed by nature, when she made them, like fire, expansible over all space, without lessening their density in any point, and like the air in which we breathe, move, and have our physical being, incapable of confinement or exclusive appropriation. Inventions then cannot, in nature, be a subject of property."
TLDR: The creation and exchange of knowledge is a positive sum game.
The cumulative nature of knowledge is amplified by the fact that any possessor of an idea may use that idea to generate better ideas that can in turn be shared with everyone else. It is this positive feedback loop that has been fueling the superlinear progress that our species has so recently become accustomed to. This progress is what is at stake whenever censorship of any form takes place.
As trivial as it seems, since thought is upstream of speech, freedom of speech is unequivocally worth everything else it might cost. As it is the most important cornerstone for a society that wants to make progress by falsifying their own bad ideas and creating better ones to replace them.
In both the literal sense (ie. Wikipedia) and the figurative sense (ie. the First Amendment), it is in the best interest of both the human collective and the individal to give information what it wants and let it be as free as possible.