Being critical is good, and we should always hold them accountable for our security. We can look to third party audits for help with that.

https://community.signalusers.org/t/overview-of-third-party-security-audits/13243

This entire article is guessing at hypothetical backdoors. Its like saying that AES is backdoored because the US government chose it as the standard defacto symmetrical encryption.

There is no proof that Signal has done anything nefarious at all.