They can force Facebook etc. to hand over the data anyway, so it does not seem like much would change in terms of the threat posed by governments.
You're making it appear as through National Security Letters were public, which they very much are not.
> "Not that I'm implying there isn't already secret requests for data"
I appreciate that you consider it worth reiterating the point about national security since I had only glossed over it. But I don't appreciate you manipulating my comment to suggest that I was ignoring that point entirely when I quite clearly did raise it.