Small correction to that article:
»Signal can also access your contacts to let you know who has the app and who doesn’t.«
Signal (the app) accesses the adress book, but Signal (the organisation) does not. The app only sends hashes of phone numbers, which are not stored after the comparison.
I really hate that nowadays Ts&Cs (and Android permission settings!) are treating a piece of software synonymous with its creator, and people are getting used to it.
The social network of the future: No ads, no corporate surveillance, ethical design, and decentralization! Own your data with Mastodon!