So, Mr. Antolliere? This is something worth understanding when dealing with the Caldari: they don’t see any contradiction here.
Civire and Deteis have been close as kin (without very often actually being kin) since before the Raata Empire. There’s even a foundational myth on this subject: Cold Wind, in which fighting between the two bloodlines is stopped by literal divine intervention.
They don’t mix (or, people being people, try to discourage it as a matter of policy), but they don’t see each other as outsiders, and “divided by bloodline” is one of the only ways Caldari don’t normally compete.
(Actually the main way Caldari run into discrimination despite the meritocracy is being of mixed blood. Pretty sure I’d never have been accepted into the SWA if they hadn’t been really eager to churn out as many eggers as possible.)
This even extends to a more limited degree to the Achura; our society was still in our iron age when they found us, but they saw enough of themselves in our culture and faith to recognize us as, if you like, poor cousins.
To a degree (and ignoring the corporations) you can think of the State as a single, great manor containing two distinct families that nevertheless live together closely, plus the Achura as long-term residents of the guest house.