I really have no idea why everyone is bashing Signal so much here. None of the concerns listed seem even slightly technical.

The only problem I have with signal is that it is:

A. Centralized (which isn't explicitly a privacy concern, but a control concern in-line with linux and foss)

B. Requires a phone number to register.

It is quite private in spite of that, and goes to great lengths to achieve that privacy. It is what I see people in the security community consistently suggest.

However, if this is a public group, are we to really be that concerned about many of the considerations Signal tries to tackle? Worst case scenario a bad actor simply enters the chat and backs everything up.

It seems like our threat model is moreso in the way of general surveillance economy concerns (and perhaps to have a slightly less public entry).

In this case, point A and B become even more glaring! Why not something like an E2E encrypted Matrix chat?