>Given how the posted described the optional `--no-sandbox` flag as "no sandbox on Linux", it's clear that they don't understand anything they're sharing, and they just want to spread FUD.

Could you elaborate as you seem to be more "knowledgeable". This flag is clear at what it does and shouldn't be shipped into production. https://no-sandbox.io/

You can have a look where they specifically chose to force it https://github.com/signalapp/Signal-Desktop/commit/1ca0d8210...