This is the worthwhile point.

If the loudest voices advocating for kindness to puppies belong to those who kick puppies for fun, it doesn't mean that kindness to puppies isn't a virtue. So the existence of free speech hypocrites is in no way an argument against free speech. I don't really understand why you even made that point--it's clearly a logical fallacy.

But you're correct that for free speech to actually matter, you need a channel in which to transmit that speech that is low enough noise. If every time you go to say something in the public square, someone stands up on a soapbox and starts yelling through a megaphone, you're not really going to be heard. And it's the receipt of speech, not the production thereof, which is the goal here.

However, your arguments for the mechanism that should be used to enable receipt of speech in the United States are not particularly compelling. Although specific laws forbidding recrimination for protected but undesired speech could help, the other side--the speech policing side--relies on relatively poor analogies.

The problem is that for criminal cases we devote a lot of attention per case. But we can't afford to devote anywhere near that much time to cases of speech; there is simply too much speech. So even if you could get people to agree upon, say, a Constitution of Freedom of Expression which would provide strong protections for unpopular but not imminently dangerous ideas, it wouldn't be implementable using the same mechanisms. It is in large part the huge effort made that helps judicial actions be relatively independent of politics.

Although I think Norway makes a good proof of concept that some things can work considerably better than what's going on in the United States, we have to remember that the United States of the past was better than the United States of the present in this regard, despite present-U.S. being more willing to restrict speech than past-U.S.. So it's far from clear that the same things will work. Cultural differences are presumably rather important. If, for example, you look at Florida these days, you have a pretty powerful argument that you want to keep a lot of barriers between people in power and the possibility of government abrogation of human rights, especially the meta-right of free speech that is the best defense of all the others. Similarly, although Germany has some of the more extensive restrictions on free speech and yet overall has a lot of freedom, you can also note Hungary's different restrictions with a rather more oppressive outcome. Germany only illustrates that you could have restrictions not that you should.

So I think fundamentally, although you present a fair number of individually good points, overall you fall quite short of making a compelling case.

An alternative would be to simply aim directly at your noise criticism above: by some mechanism, people have to be able to select the kind of voice they want to hear, rather than have it determined by whoever can spam the most or spend the most or lie the most.

Even Twitter has made some moves in that regard, with community fact-checking. Compared to the clumsy government-influenced tactic of shadow banning things deemed to be misinformation, this seems a lot less open to abuse.