It's like the 1990s, old IRC and AOL chatrooms. You can just follow a lot of randoms and get into cool threads. There are many instances that have open speech policies (which are banned by many other instances) and other instances with standard ban lists. You can choose where you want to sign up. Many of the people on HN have the knowledge to stand up their own if they want. (I run my own in Docker using a ruby tool I wrote: https://github.com/sumdog/bee2).
You can even create accounts of different Fediverse servers to get a better picture of what gets blocked/censored where. The difference with ActivityPub/Fediverse is you have choices.
Twitter, Reddit, et. al. worry so much about keeping people "safe" that they have completely killed off any diversity of ideas. Back before Reddit started their multi-year long banning-of-everything campaign, you had a lot of different voices, with a lot of different ideology, from conservative to socialist to libertarian to progressive .. battling it out with some really great discussion. Now it's all just monoculture.
The places people fled too, like Voat/Gab, are also just monoculture (Gab recently migrated to their own broken, garbage fork of Mastodon ... as if they needed a way to make the Mastodon UI worse). Voat is just a cesspool of hate, and any melting pot where people discussed ideas rationally is kinda gone.
I highly recommend The Coddling of the American Mind, a book that talks about how people today see "Free speech" as a bad thing, how people say words == violence (they don't, violence is violence, and saying words are violence show you're afraid of ideas).
I've also been reading The Strange Death of Europe, which talks a lot about migration and religious hate speech. Honestly a lot of the book is garbage and I didn't like any of the initial arguments, but I also realize it's important to read about viewpoints I don't agree with. As I kept reading, the author did make a lot of effort to interview Muslims (both long term residents and refugees) and he does make a good set of arguments for the difficulty of criticizing religion in Europe (and I don't agree with a lot of his findings, but I think his arguments and original research are worth looking at).
We really need to be careful with these new blurred lines around speech and hate and ideas and ideology and violence. Restricting things on any platform just gives people with those views, people who get banned, more validity in the eyes of people who see them as persecuted. The Westburro Baptist Church is an example of a small, non-evangelistic set of families that barely grow, who are fully supported by slander lawsuits (they're mostly lawyers). If there weren't WBC counter protests and publications against them, they'd have no one to sue, would have run out of money a long time ago, and would have needed to take real legal case work again. The great irony is the reason they still hold strong is due to protesters giving them relevance.