As an aside, I’m very much convinced that Signal’s primary objective is to gather phone numbers in order to facilitate the US government tracing social networks of people who are already of interest Their main focus isn’t on what these people are discussing, they want to know who is talking to whom first and foremost. Signal’s subpar user experience is a feature from this perspective. Due to its inconvenience for the average person, those with a strong need or desire to communicate sensitive information are more likely to utilize it.
Think of it like the Nigerian email scheme, Signal by its nature selects for people you might care about, which drastically reduces the number of people you need to track. Meanwhile, all the tracking is done server-side, which already openly collects phone numbers, you don’t really need to do much additional work there to harvest these numbers. However, speaking of the source code, it’s worth noting that Signal won’t even make reproducible builds.
There are so many easier ways of doing that. Especially when your monitor all sms traffic.
I’m pretty sure they like having as much data as they can. The policy seems to be is to trove everything and to figure out what to do with it later.