Well, it’s because you think of morals as a modern day person would. The point is that he’s a noble through and through. They are entitled and arrogant because their high society allows for it as they’ve been raised to believe they’re above everyone else and in this case, they quite literally are, with Cesar at the top of the food chain (just under the imperial family I’m guessing). Having been abandoned by his parents as a kid also explains why he doesn’t examine his own feelings further than he has to where Adele is concerned. Since he’s seen how people who are crazy in love for each other become irresponsible (his parents) he has no interest in the emotion, which is why he believes all he feels for the FL is lust.
I don’t know if you were asking the question rhetorically, but I answered it anyway. Personally I seriously love how the author has portrayed him. He’s not just pretending to be a jerk, he really is and I’m here for it.
I really wanna wipe that motherfucking smirk on Caesar's face. I don't give a shit about his backstory. How did he grow up to be such a shitty human being? Even animals have better morals than him.