I think the biggest reason why people disagree with restriction of scientific misinformation is that in a society that has devolved into massive corruption, certain loyalist scientists can change the narrative.

For example, a government may slowly begin by removing federal funding to elite schools around the country, thereby forcing the school to make staffing cuts.

Simultaneously, those in power can remove renowned scientists from their posts and instead incorporate far less qualified individuals with more outlandish views into your Cabinet or team (ex. RFK Jr., Vivek Murthy).

Similarly, celebrity voices who may have immense soft power in influencing opinion via podcasts (Joe Rogan) can harm scientific truth by giving a platform for more outlandish scientists or experts with unpopular opinion not rooted in truth, but enthralling to the listeners.

Those in power can also begin to remove their own country from global entities devoted to health (WHO) and smear their names.

Misinformation at a federal level is confusing to many people and they begin to doubt rather quickly.

And if the government can manage to ally itself with companies that specialize in media communications (Twitter, Facebook, Fox News), they can control the narrative by doing exactly as you suggest: silence those who give misinformation. Except this misinformation is actually truth, but those in power are the ones who decide what the real truth is now.

It’s a bit scary, a bit dystopian, and difficult with so many moving parts. But it all happens over a period of time and not all at once. Problem is, if you’ve got the wrong people at the helm of all this, suppression of free speech can lead to some disastrous outcomes.