This is a terrible representation of systemic oppression to begin with. It's not dealing with casteism at all but "elevating" those people to the level of their "former" oppressors
Elhokar didn't just accidentally sentence them to life imprisonment & Moash to literal death by slavery, but when the truth came out to him, he let them rot out of potential embarrassment. After all that, what does Moash get? He gets to become his bodyguard, the person who was behind all of that. Not out of malice but sheer disregard and a vast gap in power.