Crowley doesn't seem to find much value in the decanate meaning. For him, Jupiter in Libra was "sincerity in the religious instincts, which are expressed with an imaginative mysticism" (the 49-petaled rose?). He also stresses the justice and impartiality of Libra [later 'dispassionate judgment'], but combined with "seeing humanity through rose-colored glasses" and "comradeship." This is weakened by "partial material failure" - these tendencies do not serve terribly well in the world of material success and political leadership (unless supported by other indications). From comments in the Five of Swords, he, perhaps, sees such tendencies to magnanimity as liable to weak sentiment.
It seems to me from BoT that the Truce of the Four of Swords is arrived at as an intellectual compromise based on social conventions (dogma and law) in order to alleviate stress (the 'mental chaos' that surrounds the swords) and appease tensions (epitomized in the Pax Romana - again the rose).
However, such peace is tenuous - mere "static shams," so it's not a good idea to take a rest yet. The truce is not truly justified nor built on solid ground and is about to be disrupted by the Five.
He seems to find a potential for great danger in the repose experienced as a result of social harmony and conventions at the expense of the individual struggle to come to terms with one's own problems. Visually, there is a kind of determinably blind turning one's back on the jagged mental chaos in order to focus on a pleasant, but false, convention called harmony.
Crowley's comments on the Swords especially seem to relate to his thoughts about the war that was going on. The sincerity of ideas about comradeship, pacifism and impartial justice, disintegrate easily when sternness (strong will and individual authority) becomes lax, allowing corruption to work its way in at the Five.
I guess Aeon said this all much more succinctly.