It didn't say that the beta was public. If you run AGPL code on a home server for personal use and someone hacks in I don't think you should owe them code.
"Truth Social hasn’t officially launched. But users could access a test version of the platform"
> if you run AGPL code on a home server for personal use and someone hacks in
No one hacked in [1]
"we could find no evidence that someone illegally broke into the website [...] the site was simply deployed live early as a test, and without proper configuration [...] people merely used the site legitimately to register accounts and use its features"
https://sfconservancy.org/blog/2021/oct/21/trump-groups-viol...
edit: Only the users of the AGPL service are owed the code, it doesn't need to be posted publicly.