There cannot be "free speech" instances because every instance (or more generally speaking: any online community) I am aware of that claims to be "free speech" ends up being an alt-right echo chamber, a platform for hate speech, or a site to share questionable pornographic content.
Unfortunately you need moderation if your Internet platform is open to the public.
The people who make these posts looking for "free speech" are really looking for no consequence speech. They like to pretend they're fans of the town square but ignore the fact that people can get run out of the town square, they can get shouted down in the town square, and they can get drowned out by the others in the town square.
They want to be able to say hateful things without being accountable for their hate. That's not free speech as envisioned by anyone who is an actual advocate of open society or free speech.
What we have on Lemmy is probably the closest thing we'll ever get to a public square in the Internet. Someone can go and say their hateful thing. Then they can get run out of the instance they're on and go find another one. If they say hateful things and get run out of there, they can find another one. Who knows, one day they might find an instance full of like minded hateful people who don't run them out. Of course, they're likely to find that instance is not federated very well or broadly. Much like people from non racist towns don't like to have much to do with towns widely known to be full of racists.
I remember Voat which started as "free speech" alternative to Reddit. When I checked the site out the first thing I saw was an underage anime character without clothing on the front page.
Not sure if this is what we want the Threadiverse to be associated with. (Well, actually I am sure that we don't want that.)