We tend to think of decryption as a single transformation, a single spell. It brings a unit back to life (sans maintenance cost) with what may be, as far as we know, identical stats and all the knowledge and personality of the croaked unit. But it somehow shifts their loyalty, obedience, and duty to the new side. It's as if the blanks spaces in which their previous side's name were written are now filled in with Gobwin Knob—or Wanda's name.
We've had a peek now into the minds of various decrypted, but for now let me focus on the two royal brothers, Ansom and Ossomer. We see, in their own words, what they value. Ansom places a premium on tradition and on several occasions speaks about religious orthodoxy, i.e. the will of the Titans. His mindset as a decrypted unit changes, shifting these exact same values. He still believes in the Titans, switching his interpretation of the issues, however, by adopting the argument presented by Parson (though as a piece of psychological warfare or trolling, if you will), that the attunement of arkentools to non-nobles demonstrates a "new revelation" by the Titans. He is still a "true believer," but now has switched form an orthodox and reactionary crusader to a revolutionary heterodox fanatic. His motivation, his mindset, is the same. As Eric Hoffer wrote, a rabid believer is the easiest to switch from one cause to another, even one diametrically opposite in tenets and goals.
Ossomer also maintains his mindset, his values. He espouses Nobility and honor, calls Haggar's behavior gauche, and rails against the conniving of Charlie or the cowardice of Stanley. Ossomer cares about Nobility as a set of principles and esthetic values. He can try to interpret these central tenets to support his new allegiance, with it is undoubtedly a clumsy match. When his values are further betrayed by the order to violate the sanctity of parley by using yellow dwagons' acidic battle crap, he is at a loss, unable to speak to defend his side's actions. The former staunch and unflappable stalwart is no more. He is ripe for switching sides with no satisfactory argument to justify his service to GK.
Ossomers unconversion makes me think of the suggestion spell on Jill, which only worked as long as Jillian could conceivably justify to herself that she was following her values and beliefs. Once it was clear that saving Ansom could only be achieved by disobeying Wanda, then the subversion of her beliefs and desires couldn't stand.