[crazygringo]

To the contrary. America has incredibly strong first amendment speech protection. Any kind of legislation that would prevent people from reading or posting political speech unless they verified their identity, especially where it is popular, is going to immediately be ruled as unconstitutional.

That's the difference. Porn sites aren't places intended for the free exchange of political opinions so age verification can pass muster. If anyone tried to do that with newspaper sites or political blogs or anything like that, the courts would shut down that law instantly.