This isn't a targeted request for one user's Facebook messages. This is a request for every Facebook user's message. And when they don't hand over private DMs,

This isn't a targeted request for one user's Facebook messages. This is a request for every Facebook user's message. And when they don't hand over private DMs, they point and go "especially those, you're obviously hiding something by not giving us the most sensitive user data you have". It is an absurd breach of user privacy at the scale of tens of millions of Americans that goes well beyond the reasonability for a civil copyright lawsuit. This sets the precedence that if Gmail gets sued for privacy, now all our emails are leaked. Télécom companies? All of our text messages. Cloud image storage? Woops, gotta hand us every photo any American has taken with a Samsung phone! After all, it might have content that infringes on my copyright!