This isn't accurate.
Per a summary at the time, https://discourse.nixos.org/t/nixcon-2023-sponsorship-situat...
- c3voc resolved to not redistribute talks from Anduril (or with Anduril branding), but would otherwise cover the event.
- Anduril was withdrawn as a sponsor, since the venue had a policy against military funding (https://en.wikipedia.org/wiki/Civil_clause), and time constraints didn't allow for clarity about whether the event could be held with Anduril as a sponsor.
FWIW, at the time of writing this post, Anduril is a sponsor of Nixcon 2024. https://2024-na.nixcon.org/