To play devil's advocate, what about treason (or some other form of state secret sharing)? When Julius (and allegedly) Ethyl Rosenberg shared secrets from the Manhattan Project with the Soviets, should it have been a crime, let alone a capital one?
Conversely, if the government can say that certain speech is Treason, what stops it from declaring any speech it doesn't like Treason?
I don't see how you get a security through obscurity angle out of what you were replying to, assuming you are referring to the well known cryptography saying.
That's not what "security through obscurity" is about. The admonishment against "security through obscurity" in cryptographic circles is about not relying on your adversary's ignorance of your systems to protect your secrets.
So, for instance, if you are using cryptography to secure a transmission, you don't rely on eavesdroppers not knowing what algorithms and protocols you are using. You rely on them not knowing your keys.
To play devil's advocate, what about treason (or some other form of state secret sharing)? When Julius (and allegedly) Ethyl Rosenberg shared secrets from the Manhattan Project with the Soviets, should it have been a crime, let alone a capital one?
Conversely, if the government can say that certain speech is Treason, what stops it from declaring any speech it doesn't like Treason?