People start with a clean slate.
And if he doesn't have a taste of what he's missing, he has no incentive to act well.
That's not how we treat children. Or puppies.
And children are the prototypical no sense of right and wrong specimen.
It's not how we treat
tabula rasa children from birth, you're right. If a person starts out as a blank slate, you give them some rewards and privileges, and take those away as punishments.
Dazarel is not a
tabula rasa. He still has the mind of a planet-devouring behemoth. Not long ago he tried to murder us and devour our planet.
He is not a 'child' in the generic sense of 'we are raising a child.' He is not a 'dog' in the sense of 'we just got a puppy from our friend, let's raise him and train him!'
He is a 'child' in the sense of "this child was just sent to juvenile detention for trying to burn the neighbors' house down" and a 'dog' in the sense of "this dog just mauled the five year old from across the street."
As such, he needs a rather different disciplinary approach, because his slate is not blank or clean. He comes "pre-built" with intense hostility, a desire to do us harm, and absolutely no inhibitions about hurting people for personal satisfaction or sustenance. We must first condition him
OUT OF that state, before we can condition him
into a more favorable one.
Therefore, we give him a
minimal, nonzero set of privileges (like "can move around instead of being locked in a cage, gets reasonably tasty food,") until he proves that he at least
knows how to behave. Once he has behaved for long enough that we know he has comprehension of what "behave properly" even means, then we can start giving him more privileges on a provisional basis.
Dazarel has
already started disrupting us and undermining us, in our very first interaction with chibi!Dazarel he was trying to take potshots into our conversation with Maya.
We do this all the time with children.
We start them at a base level of responsibility and trust. If they act well, they get the keys to the car, longer curfew times, no formal checkups on their homework or computer time. If they act badly, they lose car privileges, the computer gets moved to the living room, et cetera.
That's because normal children start out as blank slates with (on average) normal human instincts to honor concepts like fairness and reciprocity. Children require training to bring these instincts out, but they almost always exist, and in the rare cases where a child is a complete sociopath/psychopath, it takes time to figure this out anyway, so there's no harm done in reducing privileges gradually as it becomes more clear what the problem is.
By contrast, we honestly don't know whether Dazarel has such concepts or whether we're going to have to
teach them to him.
He's not a member of a species of social animals, for one thing...
Hell, the most successful prison rehabilitation schemes in the world are in Scandinavia, and they start out with a base level of privileges and the like, which are not taken away unless there is provable reason to do so. Anders Breivik, who massacred a bunch of kids, started with a TV and game console in his room, and that was considered normal.
That's because in a Scandinavian prison, we don't have to worry about the inmates doing much actual harm. Dazarel has considerable potential to do harm by saying the wrong things to the wrong people, IF he knows certain things that he might well know, or IF he takes it into his head to be sufficiently disruptive.
Once the Sealing is fixed and the alien army is dealt with in such a way that we know what level of infohazards we have to worry about around any remaining aliens, we will have considerably less reason to worry about what Dazarel has to say. That time is
later, not now.
Daz is not going to learn much very fast in isolation besides stewing in anger and resentment.
Us saying "Kakara will personally vet all Dazarel's conversations" is not the same as saying "Dazarel will be isolated." The "Dazarel is isolated" option was 'head-dragon' and that already lost.
This is the "Dazarel gets limited interaction with the option on more once he's proven capable of earning some trust from us." He doesn't
start with very much trust because he's not an innocent newborn child.