Sounds like you haven't read the post in question, which the article links: https://www.facebook.com/dubilet/posts/10157903866578552

Dubilet makes some insightful points:

- That having a centralized legacy system creates a single point of vulnerability, unlike peer-to-peer encryption.

- That the app can be installed on a special-issue smartphone to avoid hardware backdoors and risk of compromise from other apps.

- That the status quo (politicians use chat apps anyway for lack of an equally convenient certified option) isn't secure anyway.