The idea of non-deletion seems to keep coming up again and again in technology. From Usenet spam to abusive Facebook apps, I find myself wondering if being forever saddled with every abusive smart contract someone ever wrote is really a desirable trait in a long-term planetary-scale system.

Remember the 1990s and early 2000s when there were tons of easily discoverable forums? Moderation was less of an issue -- each forum was someone's fiefdom, but there was an abundance of choices and communities available at each choice.

The solution to censorship definitely isn't non-deletion. Usenet died for a reason and 4chan is fringe for a reason. The solution to censorship is a healthy choice of venues, good discoverability, and low/no switching costs. Basically, modern phpbb forums or discord but searchable.