The phone itself may not be secure. Maybe they should include gmail, schwab, camera, microphone, amazon and every other thing in their description. Literally this is FUD.
Fear that using a "secure" messaging app on your rooted phone will expose you to consequences.
Uncertainty that your communications are secure when using your phone with the "secure" messaging app.
Doubt that using the "secure" messaging app is secure.
yes, it's FUD.