Simple: The oppressive regime in question can deny you a certificate thereby censoring you. Some also require you to use a particular certificate, thereby creating the illusion of security while being able to intercept, interdict, or MiTM information any time they like or continually. Here's an article that touches upon it superficially from 2010, and also notes that private companies are already selling these capabilities to authoritarian governments: https://arstechnica.com/information-technology/2010/03/govts...