Re: Why? Because you trust your government?
"if I told all my friends they have to learn and implement PGP if they want to email me the latest joke or get my latest musings about where to go for dinner, I'm pretty sure my mailbox will be suddenly barren"
"As for data encryption, well I don't see that my personal data is worth it."
But each person places a different value on their data. Also: you're presuming in this statement that "the man" isn't simply on a fishing expedition looking for reasons to throw people into the fire.
As Cardinal Richelieu said: “give me six lines written by the hand of the most honest man, and I’ll find something in them to hang him by.”
Better safe than sorry, mate.
"I have firewalls and AV that have protected it up to now, if The Man wants to see it, not much I'll do will keep him from it for long."
That's a completely wrongheaded approach to this problem. You are absolutely correct in that you have no ability to keep a dedicated state-level actor out of your data. At the end of the day they can deploy physical assets to tap your data and at that point you're right fucked.
But the point here isn't to prevent the MIB from sneaking into your house while you're out. It's to raise the cost of fishing expeditions and automated searches for dissidence so high that they become non-feasible for state-level actors to engage in. Or, at least, that they go burn some other witch instead of you.
You're not going to stop 007. But you might stop the local council from abusing their access to meta-ECHELON and using the fact that you put out one too many bags of garbage to hit you up with a fine.
Or maybe you engaged in some "extreme" rumpy pumpy in front of a window with the blinds open. It's bad enough the local puritans in power could probably throw you in the brig for a lifetime. Why give them the power to slap you with an "internet pedo child molester" lifetime tatoo because you also happened to be streaming it to likeminded folks elsewhere?
I've accidentally been e-mailed XLS dumps containing the entire customer records database for a company, including tens of thousands of credit card numbers*. In how many jurisdictions could I be burned as the witch simply for being the recipient? I can think of three off the top of my head, and that's three too many!
By raising the bar for automated snooping by state actors I am raising the cost of automated witch hunts. As someone who qualifies as a witch to oh, so many groups, I'm very interested in keeping their costs as high as humanly possible.
*fortunately I was the only one who got this mail, and it never left the corporate firewall so we were able to deal with it internally, but still...