They are the ones who follow their true friends leads.

One of the many reasons why I have no chemical habits - people trust me with their secrets.
Used to hold a security clearance, so I'm accustomed to keeping things to myself.

We exist, but many of us belong to the Old World and an older order. The term "sub rosa" dates back at least two thousand years (and probably more, but the dead haven't mentioned it).
The New Order has social media, which keeps your private DMs for years (Twitter is just the latest), and periodically leaks them. Remember the Fappening? Snapchat's non-disappearing message problems? Facebook's data "sharing"? Etc., ad nauseam.
This is how Telegram, Signal, and even PURE came to exist. Every Evil Empire needs a Rebellion. Action and reaction. It's just physics.

But I am that friend.

Straight up, I always keep a confidence. When someone confides in me, it's in the vault. When someone betrays a confidence, they actually sacrifice their own self respect in the process. High cost, zero gain.