Governments routinely fund the development of secure and open communication systems because they themselves benefit from having such communication tools which can be trusted. By the logic presented in this "essay", one shouldn't be using the internet at all. What you need to check is whether Signal's technical claims about its encryption is true or not. There is nothing in this article that raises any question on Signal's encryption. We already know how much data Signal has on its users through their responses to various legal subpoenas over the years (spoiler: its pretty much nothing).
Here are some cool links for you to check out:
https://signal.org/bigbrother/
https://www.aclu.org/news/national-security/new-documents-reveal-government-effort-impose-secrecy-encryption