But disinformation isn't just incorrect information. Disinformation is false information seeded with an intent to mislead the population. The person who "gets to decide" what is disinformation is effectively the person who is planting the disinformation.

Once the disinformation starts to propagate then the downstream propagandists may believe they are spreading legitimate truths, but ultimately by definition the disinformation can be traced to a source that intended to deliberately disinform.

Also, not everyone around us needs to be gullible for disinformation to work. In the US for example we live in a country where national elections are routinely decided on razor thin margins, where just a couple of percent or less can flip the results. We also live in a nation where 32% of people believe in ghosts [0]. So there are enough gullible people for the type of disinformation that wouldn't persuade a reasonable person to still yield powerful results.

[0] https://www.nytimes.com/2021/10/28/style/do-you-believe-in-g...

This is the fundamental and intrinsic reason for concepts of free speech.

The power to control what can and can't be shared between people corrupts just like any other power.

We can't trust individuals to distinguish misinformation from "I don't like it" or whatever else.

So we shouldn't. Route around the unsolvable problem. Find another way.