There are of course rare cases when someone acts on misinformation to do something harmful. I can easily think of several examples of bad reporting from supposedly reputable media outlets that caused a ton of damage over the last year.
Conversely, most true information does not cause harm either. But some true information does cause harm.
In that sense, I think the veracity of the information has little to do with the risk of harm, and that we should not allow this trojan horse for free speech regulation to take hold. For whatever problems free speech has, trying to stifle it is just not going to provide the benefit that people think it will.
The Iraq war was based on misinformation. It did cause perhaps the greatest harm in the last several decades. However, that was “officially sanctioned” misinformation directly from the government (whether they believed it in good faith or not). I think before doing anything to limit the flow of information, consider whether the proposed framework for suppression of misinformation have caught this. Worse, if someone knew that the WMDs were not there, and could have corrected that disaster, would they have been considered misinformation?
We have already seen this in action with the tech companies giving very loose directives to their content moderators to remove certain types of misinformation. A popular youtuber was censored for telling people that masks are a good idea back in March. The official information at the time was that they do not help. The truth was that they obviously do, and now you get censored for saying that they don’t help. If someone asks honestly about something suspicious related to the election, or believes a voting rule change was procedurally unfair, without paying any mind to the weird conspiracy theories, they get moderated. Because it sounds like “claims of election fraud” and the 3 seconds that the moderator spends on it don’t allow for nuance. Or the hunter biden “misinformation” that wasn’t. That basically means that the word of the US Government (particularly the Democrats) is the “true information” and anything else in conflict with that is misinformation. And that’s a pretty bad place to be. In practice, this just doesn’t seem to work, and does more harm than good.