It is not the role of the judiciary to define what is just of unjust: they just need to make a ruling based on the law. There is really no difference if someone is paid $20k or $90k: you always must discount that rate if you are not an hourly employee. It is not theft: it is at-will employment and nobody is being forced to take it.

Also, the ruling is only being postponed:

--- “Due to the approaching effective date of the Final Rule, the Court’s ability to render a meaningful decision on the merits is in jeopardy,” he wrote. “A preliminary injunction preserves the status quo while the Court determines the department’s authority to make the Final Rule as well as the Final Rule’s validity. ---

If the law was clear, then there would be no difference between whether the decision is done during the current or future administration. It seems that there is enough ambiguity that the course of action varies depending on who is in power, which appears to indicate to me that the overtime rule by Obama's administrations was on weak grounds regardless.