Facebook can't get a warrant (just like you or I can't get a warrant either), only law enforcement can get a warrant. I'm not sure if you're suggesting Facebook go to the police and file a criminal complaint under some law, and try to convince the police to get a warrant. Or maybe Facebook's lawyers could subpoena for discovery or something. I'm not sure. I'm not a lawyer.

It would be good to have a legal overview from someone that is actually familiar with relevant law.