She summoned some big tech firms yesterday to tell them how unacceptable it is that the police can't read encrypted messages.
All you are really doing is making it inconvenient for normal, law-abiding folk to use strong crypto. A suitably motivated attacker (think ISIS, al-Qaeda etc.) could adapt to a world without crypto using some kind of steganographic approach (three poop emojis and a Miley Cyrus gif = blow the building up!). Every approach you take could be manipulated by the bad guys to their own advantage.
Which is why a lot of these technologies are targeted. Not because encryption makes it harder for enforcement agencies since there's always been a plethora of ways to communicate in secret. But because gaining back doors to these applications makes it easier for them than it's ever been.
Sadly the point enforcement agencies always overlook is they're basically just fighting a game of "wack a mole". Encryption isn't something that's going to go away. Not even if you legislate against it. People know it exists and there are a thousand different ways to run software on your handset - even just via web sites directly thus bypassing all the controls for side-loading native apps. So all this posturing about the "evils" of WhatsApp is just a monumental waste of everyone's time.