Would you be ok with those other forms of slavery in published RPGs, or are you mentioning them to make a rhetorical point?
As I've said many times before, it really depends on the game.
I'll bring up Spire again. Every single drow is forced into a "durance"--slavery--for four years, starting in their late teens, and at any other time as a legal punishment for a crime (while there are no cars in this game, it's the type of setting where "driving while drow" can be enough of a crime to be arrested and re-enslaved for). The drow in that game only live to be about a 100, so four years is not an insignificant length of time for them. The drow are forced to work for the alfir (high elves), who can do whatever they want with them, physically, mentally, or sexually. If the drow is
very lucky, they may have learned a useful skill, or have served their durance being a pretty piece of art to be looked at but not harmed. They are often not that lucky at all. One of the sample adventures has drow who have been surgically modified for artistic reasons.
The entire game is about how messed up this all is, about how the alfir have tried to break the drow, and how many drow
are broken because of this. How the alfir have made important parts of drow culture and religion illegal, both to keep them in line and to give the alfir another reason to arrest them. About how this system has affected both the drow and the alfir. The point of the game is to play as a drow fighting against the alfir, but the game straight out says this fight
will eventually kill you.
It literally doesn't matter if the game has slavery as evil slavers attacking villages in order to round up new slaves, or if the slaves are there because their poverty-stricken parents tearfully sold some of their children so they could feed the rest of them. What matters is that the game treats the institution properly. Not just as an afterthought or as a way to show that this is the bad guy you get to kill this adventure.
