You can't secure what you can't control, but control alone is not security. People mistake control for security when they say the iTunes App Store is safe because it's curated, or that only registered taxis are safe. The iTunes App Store and registered taxis are controlled, but that does not automatically imply that the control exercised over them is perfectly secure or even that their criteria for control is in your best interests.
Mokalus of Borg
PS - Spoiler alert: Apple is not out for your best interests.
PPS - Neither is any other for-profit corporation, just to be thorough.