Why are phone records private?

In the four days since USA Today reported that the NSA has millions of phone records, millions of decent, hard-working Americans have said, "So what?" I think there are two reasons for this: first, data security seems like an esoteric and hard-to-understand sub-field of computer science, which makes people disinclined to think about the problem; and second, most people need concrete examples to understand things clearly.

How about this simple, concrete example: ABC News is reporting today that reporters' phone logs are being used in the ongoing CIA leak investigation.

By figuring out who reporters called and when, and who called the reporters, investigators—and heck, any modestly-trained chimpanzees for that matter—will have little trouble figuring out who leaked information to them.

Let's all say it together, shall we?

The right of the people to be secure in their persons, houses, papers, and effects, against unreasonable searches and seizures, shall not be violated, and no warrants shall issue, but upon probable cause, supported by oath or affirmation, and particularly describing the place to be searched, and the persons or things to be seized.

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