> They just have to decide you're suspicious enough to confiscate equipment and bar you from entry.

That's fine with me. I don't take anything to a foreign country which I'm not willing to lose, and I have no problem turning around & heading back home if the country I wish to visit turns out to have unacceptable rules.

If someday I visit someplace that has an implicit rule, 'all visitors must have Facebook accounts,' then I'll just go back home.

Hold on, once again, because you're oversimplifying the situation here. You might be comfortable being turned back at the US border, but there are plenty of people who aren't in that situation --- they're children, or are coming to take care of their children, &c --- and being turned back at the border can mean it's very difficult to return to the country under any circumstances for years afterwards.

I think you're looking for an argument, but I'm not. It's always been possible for a country to turn a visitor away (talk to folks who've been to Israel and try to travel to an Arab country …), and that does have consequences which one must be prepared for.

I'm certainly not going to claim that 'all your password are belong to us!' is a good or desirable policy, but I am going to claim that anyone who travels between countries must be prepared to deal with the local regime, no matter how ill-conceived its rules may be.

One of the pieces of important advice I am planning on passing on to my children is: Never have children with someone who has citizenship of a country that you don't.