[SlowRobotAhead]

You could say that, but it would be fundamentally misunderstanding why the US Government needs TOR users.

There is no extra safe guards to encrypted email that lives on a server the more users you add. It doesn't matter. It was a point to point transfer once. All emails are SSL/TLS sent anyhow.

TOR is a different thing. It's active user browsing. If only US spies (example) used TOR, it would be pretty damn obvious what they were doing or at least show that this was vital traffic to inercept. But add in millions of normal users and it's much easier to keep your nefarious deeds hidden by just blending in with the crowd.