Here’s the facts:
- Protesters have been coordinating using Signal
- Breaches of private Signal groups by journalists and counter protesters were due to poor opsec and vetting
- If the feds have an eye into those groups, it’s likely that they gained access in the same way as well as through informants (which are common)
- Signal is still known to be secure
- In terms of potential compromise, it’s much more likely for feds to use spyware like Pegasus to compromise the endpoint than for them to be able to break Signal. If NSA has a Signal vulnerability they will probably use it very sparingly and on high profile foreign targets.
- The fact that even casual third parties can break into these groups because of opsec issues shows that encryption is not a panacea. People will always make mistakes, so the fact that secure platforms exist is not a threat in itself, and legal backdoors are not needed.