She did have four Black step-siblings.  If she's sincere about identifying with Blacks, and if she's not doing anything illegal or harmful, why not let her be Black?

Of course, most of us haven't seen her up close, so perhaps those who've worked with her and served on the NAACP with her would have a better idea of her level of sincerity.  Or they might be intolerant themselves.  More info, please.