Logic?
"If anything, this suggests encrypted communications is working – federal and state investigators who need warrants to spy on people are giving up on crypto-secured natter. It's not worth the time."
If encrypted communication is used by criminals and terrorists in performing their evil deeds, then surely they should be spending more time spying on people who use encryption. Then again, it may be that encryption is mostly used by people who don't want the Feds listening in on confidential business discussions or 'romantic' conversations.