Slavery in romance manhwas

One question, why even include it if there is not going to be any type of message as to why slavery is in fact bad?

Why do many times the slave is made out to be a bad guy for "betraying" their "owner"?

It's so fucking weird, i like "Villains Are Destined to Die" but i do care that the guy betrayed the FL, he could have murdered and i still wouldn't have given a fuck. "But she freed him!?!?!" Guys she bought him