Mrs Hinkson died November 26, 2014. She was for a long time a member of the Martha Graham Dance Company. She is considered to have been very influential; she was awarded the Martha Hill Lifetime Achievement Award. She studied on a university, she taught at a university and, according to the Wikipedia article, she influenced both ballet and dance.
The reason why Wikidata knows about it is because I took the time to add them. In this way I can point to the failings of my approach to adding data.
When an article does not have relevant categories, typically I will not add associated information. Mrs Hinkson is highly notable and the only category that adds information for her is: "American female dancers".
There are many things I will not state. Nationality gets you in conflict in too many ways, so does race, religion. The consequence is that Wikidata is fairly uninformative about this. From a diversity point of view, it is not that great.
I think when race, religion and nationality play a big role in an article, the Wikipedia categories may not be all that inclusive. To find if this is true, takes some research.. The results I am looking forward to.