Because it is a meaningless term, able to be sculpted to what ever you want at the moment.
Finally, it would be a masterstroke if those great powers honestly bent on peace would form a League of Peace, not only to keep the peace among themselves, but to prevent, by force if necessary, its being broken by others. The supreme difficulty in connection with developing the peace work of The Hague arises from the lack of any executive power, of any police power to enforce the decrees of the court.
For progressives, all there is is government. Nothing else matters.