Yeah, due to China's block of Google's services, Chinese companies cannot include Google Play Services on their devices, so they include 3rd party app stores (like Kakao or the likes) that only work for the Chinese market. Same thing with Amazon; because they include their own app store and the way they license things, they are free to use Android's code but cannot include Google's services.
There are, however, ways of installing the App Store, just not too savvy on how exactly you'd go about that and I do believe this varies per device (and if it's a generic Chinese tablet, finding the right method might prove tricky).