And your reading comprehension still hasn’t reached above grade school level, I fear…
But to take it seriously: The writers put that monologue in. They made it unprompted by you or other NPCs. They clearly demonstrated that Gallywix has been thinking about the morality of the situation. Why? Because they wanted to show that Gallywix is perfectly cognisent of his moral responsibilities, but is deliberately ignoring them, making him willfully evil? Sounds a bit strange to me. He makes the argument against his position, and leaves it standing unopposed.
On the other hand, if it was used to highlight that he isn’t happy with his own role, the monologue would make a lot of sense to me.
I don’t claim to know which of these options it is, but I do think it’s quite stupid to be fully certain that it’s just a joke.