"Good slavery" is way too common in manga, but I'm not easily offended and this is strangely funny. That said, I can't quite understand where the young Miss Lady is coming from or why she takes such insistent pride in her poverty.
Is she fallen nobility? Does she really think commoners are of lower social station than slaves? Just delusional???
I suppose it doesn't matter. Her back-and-forth with the baffled straight man Commoner is priceless.