It's the part of the bottom of the totem pole that moves first because it's on the front lines.

Each of them have long, complex procedures they have to follow in many cases, and some exceptions. A court might well be able to issue a preliminary injunction faster than an agency can do notice-and-comment rulemaking.

Agencies specialize at problems that don't need a simple rule, but rather need large amounts of meticulous and tedious special cases. They've got more bandwidth, but not necessarily shorter latency.