The best analogy is that I support your right to spew your hate speech if you want, but I'm not going to open my house and let you do it in my living room.
Most sites eventually decide that they don't want to be associated with that speech and clamp down.
The chance of negative social interactions occurring goes up with the number of interactions, not the number of participants. In a dense community, this is O(N^2). In a sparse community, where participants subdivide into cliques that have little or nothing to do with each other, it approaches O(N).
Specific social features all have different effects on the degree of interconnectedness on a site. In particular, things like unified user profiles, retweets, direct-link shortcuts to either user profiles or posts, navigational links, and real-time engagement increase the interconnectedness. Things like no-comment links (np.reddit), time delays, separate domain names for different subjects, subreddits, few links between different communities, separate user accounts, etc. reduce the interconnectness. Social sites exist on a spectrum from individual communities (4chan, HN, forums, etc.) to densely-connected but partitioned networks (Twitter, Reddit, Discord, and Facebook) to publishing platforms (YouTube and Wordpress) to sitebuilders (SquareSpace, Wix, etc.) The latter end has virtually no problem with miscreants because it has virtually no social interaction; the former has a big problem with miscreants but has enjoyed the benefits of higher growth, higher engagement, and more ad dollars, except that if you go too far toward the community end, the community self-limits its size through rules and customs before it becomes big enough to monetize.
Wordpress has benefitted from slower growth - because they're basically a publishing platform rather than a community, they don't face the same problems that being a community has. (They didn't get the benefits, either, which is why Facebook is a $500B company and they're not.)
I personally left the site after eleven years. Steve actually permanently banned me after I had pointed out a few instances where racism was not only allowed to live, but seemingly encouraged.
Or if someone feels like it.
Occasionally I'll be logged out of reddit and see the new defaults and my god, I feel like I'm getting dumber.
Also, with a lot of these platforms, you're also getting freedom of distribution, which is not a right guaranteed by law.
Whether tech giants or smaller businesses, they all do advertisers' bidding, and the advertisers themselves have the insipid idea in their heads that having their ads show up alongside non-PC content is going to somehow associate their brand with that exact content, as if it's an endorsement.
There was an issue on YT where a video from ISIS containing a beheading was monetized. Advertisers were directly funding terrorism in that case (until YT interceded). The same happens all the time with other anti-humanitarian videos all the time.
I agree that there has been some over-reaction, but let's not pretend it's not a problem.