If one wants to avoid having contact list on server, they don't have to force everyone to use government issued and fully controlled identifiers. They can do lo

If one wants to avoid having contact list on server, they don't have to force everyone to use government issued and fully controlled identifiers. They can do local contacts storage, and use emails... or even random numeric identifiers (anyone remembers ICQ?). I think novok is right in their uncle comment -- the decision to force people to use phone numbers, with all the related privacy problems, was to increase adoption. And we should be upfront on it: "Yes, Signal could have made things more private if they would allow usernames/emails/UINs... but instead they decided to force phone numbers to get market share as fast as possible. Yes, this means millions of people are forced to share the Signal contact list with Facebook and Google, but it was worth it -- look we have 40 million users now!" There is nothing wrong with reducing user's privacy in order to get more market share. But let's not claim that this was for users' benefits.