> As I pointed out above, anyone can get a website and domain name.
I wish this were true, but I don't think it is anymore.
If you post or host anything remotely controversial, expect to have your site DoS'd off the internet. How can that be avoided? Well, mostly through the help of one of the big boys (Cloudflare, Google Project Shield, etc). What happens if they decide you're a despicable, e.g. Stormfront? You're pretty much SOL.
Sure, there are plenty of other mitigation services, but they generally get pricey - not only pricey, but asymmetrically pricey. When your detractors know that they can burn through your war chest by expending a fraction of what you lose, that's clearly an unsustainable position.
The same is true for DNS. When every registrar can be pressured into denying you service, you don't have a lot of recourse.
That's not to mention the well-worn argument that, in a hypothetical era where the vast majority of traffic is via one of the big name sites, going off on your own is basically analogous to having your soapbox relocated from Hyde Park to the industrial wastelands. Are you still technically able to speak publicly? Sure, but the original intent of protections on speech is nowhere to be found.
I don't have an answer to the subsequent question of what to do about it, beyond supporting decentralized technologies. That's a tough one. What I do know is that the idea that anyone is able to provide their own platform if deemed undesirable may be comforting, but doesn't really hold up.