Just because a cryptographic protocol is secure doesn't mean a given implementation of it is secure.

Just because an implementation of a cryptographic protocol is secure doesn't mean the way its users use it is secure. 

 Users are the worst for sure! 😅 

 My password written on a post-it has yet to be hacked. Checkmate. 

 No one has cracked the cryptography that translates the holographic universe to 3d meatspace.