i think they mean that signal on desktop does not encrypt their content at rest, which is acknowledged and not an issue they are intending on addressing.
But it seems to have recently changed? I’m learning thus as I wanted to find a source.
Source: https://candid.technology/signal-encryption-key-flaw-desktop-app-fixed/
You’re right but the issue is also made worse by OSM not having a system of reviews for POI’s, or the ability to add arbitrary photos and possibly other data. This is critical to building the community I think?