Federal Courts don't usually grant a subpoena. Notably, the notice of third-party subpoeonas from this case wasn't even filed in the case.

https://www.courtlistener.com/docket/64436614/federal-trade-...

Rather a lawyer that is admitted to the case uses his power as a representative to serve a subpoena. These are usually NOT reviewed by the judge or court first. The person receiving a subpoena can ask the court to quash the subpoena (basically void or modify the subpoena) if they believe the subpoena is inappropriate, unduly burdensome, or whatever else.