If Twitter outright stated "We did not shadowban Scott Adams or otherwise place any restrictions on him, and do not intend to do so in the future", that would be sufficient for me. Usually corporations and people don't outright lie.

Do they also need to assure you that their board of directors is not composed of reptilians? Do they need to respond to every accusation and conspiracy theory, or just the ones without supporting evidence?

It seems like they'd owe it to their investors to at least comment on the ones that make it into news articles, and appear to be worrying a small percentage of their userbase.

Keep in mind, they have a Privacy Policy, a Terms of Service, and dozens of pages on their support site that cover all sorts of issues in great detail. Surely it's at least worth a sentence in their ToS and a tweet from a middle-manager, even if the accusations are completely bogus?

Personally, I put the probability at around 30%, so I think it's more likely to be false than true.