Isn't this how keychain works?

This is clearly not remotely executable, it needs to be run on the device that is signed in.

Say you visit facebook.com, your password is in the keychain, so the keychain must be decrypted to return the plaintext password so it can be passed in the password field to facebook.com

This is how keychain works isn't it??

You can view your entire password list in Safari Preferences - it does the same thing.

So this is nothing? Someone has written a command line version of this same tool.

Am I missing something, this seems to be normal functionality of the OS for a signed in user.