I like how most Beastkin are just humans with animal ears, and then you have the Beast Ming who’s just an anthropomorphic lion.
There was one that was just an anthropomorphic tiger back at the Black Market
Also, am I forgetting something? If the Beastkin slave trade is legal, why was that auction Elsa and Evie busted up a few chapters being treated like it was illegal?
Allowing myself some very ungrounded speculation, it could be that there might be legal and illegal ways to go about enslaving someone/owning slaves, and the Beastkin slaves were either obtained illegitimately or the method of the Black Market slave trade is illegal (private auctions that may interfere with a government attempt to track all slaves in the country, which would be important if documented slaves had some form of legal protection that undocumented slaves aren't given). Alternatively, it could be that the trade is illegal, but the King has implemented some policy that boils down to "It's illegal on paper, but there's no punishment if you get caught, so it's legal in spirit".