A “rip the scab off, deal with pain by headbutting it, us tough guys have fun playing bloody knuckles, weaklings should be driven off or forced to adapt” is one take. D&D is a broad hobby, and there is room for this and there is room for people want a better treatment.
Here you are already wasting unneeded word count setting boundaries to the imagination about kind of slavery the setting presents, kind of demonstrates there is a need. I think it might need to be more than sentence, but at least a short sidebar.