I suspect there is a bit of parallel construction going on

They might already know for a fact that illegitimate use cases are the primary use case, they just cannot use any of their evidence in court

So they are seeking a way to legally obtain the information they already have, basically

It's shady but my understanding is it happens kind of a lot in modern policing. They can get illegal information much easier than legal information. So the illegal information sort of forms the justification for the time and money spent pursuing and gathering the same information legally