This is not a comment about if journalists homes should be more sacred than other people. Some countries do give journalists extra legal protection against this, but I do not know US law in this regard.

To my understanding, a US search warrant authorize law enforcement officers to search a particular location and seize specific items. The requirements are:

1# filled in good faith by a law enforcement officer 2# Have probable cause to search 3# issued by a neutral and detached magistrate 4# the warrant must state specifically the place to be searched and the items to be seized.

There is nothing about the owner of the location. It can be a car, a parking lot, a home, a work place, a container, a safe, a deposit box in a bank, and so on.

The significant question here is about probable cause. Why were those items interesting for the FBI to collect? Are they looking to secure evidence against the leaker, and if so, what was the specifics of the search warrant? The article states: "The statement gave no further details of the raid or investigation".

Probable cause should not be about preventing journalists access to documents they already got, as that would be like going after Barton Gellman.