More like "this is how you creep in justice". You set a date and politicians will spend months determining what's too long/too short. Or in this case, the judges may not get a unanimous ruling as easily. The article mentions that this is a DC appeals court that establishes this, and several other circuits have rules otherwise.

The fastest way is leaving it vague, waiting for some court case to set precedent on what is "too long" and use that as a reference for future court cases. Or in this case, it may in fact go to the supreme court who will be able to determine a more concrete time (or just throw it all away and doom us all).