YOU make a poor argument. All email correspondence with external servers (I believe it to be 90+ percent of all correspondence) is not encrypted at all, and the rest is bypassable if Protonmail wants or forced to decrypt it. This is just a security theater.
True security is when the provider can't decrypt anything under all circumstances, even under coercion.
Your argument boils down to “govt can force them to change how they do that”, as opposed to a flaw in their approach.