She was but if you notice TVD completely negates slavery in general. If you go back to the 1864 flashbacks it’s not mentioned once, when Alaric is going over the Civil War in class it’s also not mentioned, and when Bonnie was talking about her ancestors from Salem again it’s not mentioned that they were slaves or even free slaves. It also makes no sense that Emily would travel from a free state to a slave one. Plus Damon was a Confederate soldier who left because he “didn’t agree” which was vague af and probably an opportunity to save the implications of that but chose not to because as far as Plec and Williamson were concerned slavery never existed and was a fairy tale.

TVD chose to set it’s show in Civil War era Virginia and completely ignore the context of that which is why Emily ended up being called “handmaiden” even though we knew she was anything but. Just look at how Katherine treated Emily, that’s not how you treated a handmaiden.

In fact, the only time Slavery is acknowledged is in TO with Marcel, but that was just to serve the “white savior” complex and even ignored the context of that from there after. When Marcel talks about his past it stopped being about slavery and about daddy issues to make Klaus seem like a good guy for letting Marcel have basic human rights. Which is very telling to Plec’s mindset.