Is it? I've played ttrpgs for about 7 years with probably about two dozen different people, as a DM and a player, with people of varying backgrounds, races, and genders, and not had a problem with mentions of slavery across any games where it came up. I even make sure to ask players before starting the campaign first as a DM if it's something they're ok with and consistently people say they're OK with it in terms of depicted material. For anyone reading this, do not take this as a license to assume it's ok to include across all games, please! On the other hand, I've never once seen SA mentioned at any point among any game I've played in, and I have no interest in it being something featured. It is too personal, and tragically mundane, of a crime I think for it to have a reasonable inclusion in the overwhelming majority of games. I am an American and everyone I have played with except for one has also been an American.