> Intuition pump: imagine the postal service opening every letter to check to see if someone's organising a letter writing campaign sending abuse to George Washington
Just on this specific point: this is not a particularly weird scenario at all. There are very strong rules about what you can and cannot send in the mail, and these rules are enforced. The most obvious example is the Comstock laws, which regulate "obscene and immoral materials" sent through the mail (including things like information about birth control). They're from the 1800s, but several are still on the books. It's not a strange concept at all in American law to regulate what can and cannot be sent through the mail.
Just on this specific point: this is not a particularly weird scenario at all. There are very strong rules about what you can and cannot send in the mail, and these rules are enforced. The most obvious example is the Comstock laws, which regulate "obscene and immoral materials" sent through the mail (including things like information about birth control). They're from the 1800s, but several are still on the books. It's not a strange concept at all in American law to regulate what can and cannot be sent through the mail.