Personally I have doubts about this canonical view of the founder. Dower (Embracing Defeat) writes compellingly of many flip-flops of convenience where militaristic fascists became democracy loving America cheer-leaders overnight. Given Ueshiba's known terror of capture and incarceration (his own cousing revilied him for abandoning Deguchi during the second suppression), it's not hard to imagine a position of convenience.

As you mentioned, spirituality was no brake on war-mongering. Deguchi and Ueshiba were ardent supporters of the most vile of terrorists and assassins. See Amdur's Dueling with Osensei ("Head in the Clouds, Feet in the Muck") as well as Thomas Peter Nadolski, "The Socio-Political Background of the 1921 and 1935 Omoto Suppressions in Japan" (a dissertation) where he notes that Deguchi offered a Colonel Hashimoto (IIRC) the services of one Ueshiba Kenshi as personal bodyguard. This colonel would be executed by GHQ for Class A war crimes.

CAVEAT EMPTOR.