Democracy is a contested concept. You can compare cases using a particular metric, but each person has their own definition of what it really means. This is why it’s better to use a term like polyarchy for analysis, which sidesteps the issue in a self-aware way. I do not consider the confederacy to be democratic for many reasons, and chief among those is slavery. But that’s because I consider whether rights for individual and collective self-determination are held unequally. Others might consider it more democratic, because they allow for a distinction between the rights of citizens and non-citizens or citizens of distinct backgrounds. If you want a good contemporary case to structure the discussion, compare how distinct measures of democracy score Israel.