You are assuming that disinformation is an absolute thing and that the state and governments tries to fight it for the common good. What I see around me is that state is a prime producer of disinformation which also already controls the most effective vectors of civilian propaganda (namely schools and TV), in addition to the dedicated military units.
What governments are trying to fight is information going against it's own propaganda. Raising critical thinkers goes against that (we have seen that even just asking questions was a crime-like action during covid), which is one of the reason education level is being sabotaged.
While it is a noble goal, we've seen in the past few years how susceptible people are for disinformation. Just see how many people absolutely ate up Covid/Vaccination disinformation. See how many people are still ignorant about climate change and believe the bullshit they're told by the fossil fuel lobby. Or even more fundamental; see how many people are susceptible for advertisement - it's basically the same.
You'd wish that people were critical thinkers. But that's not what our consumerism-oriented media landscape has been working towards in the last 50 years. Quite the contrary; "buy, so everyone will like you!" We've been trained to be brave little consumers and to eat up our daily share of capitalistic propaganda -eh- I mean advertisement.
The economic incentive to create as many mindless and uncritical consumers as possible has left much of the population unable to think for themselves.
So, before you can have your censorship-free utopia, you first need to raise the level of informed and critical education. And that's not going to happen while the economic interests need the population susceptible for advertisement.
States aren't event close to being the prime producers of disinformation. Exactly as libertarians ought to suppose, states are being comprehensively outcompeted by private industry in that respect.
What governments are trying to fight is information going against it's own propaganda. Raising critical thinkers goes against that (we have seen that even just asking questions was a crime-like action during covid), which is one of the reason education level is being sabotaged.