My 2p:
* Poor, insensitive choice of words from SH for sure, but if she'd have asked what the person's heritage was, or where her ancestors were from, would that also have been racist? And whilst its true that question would be unlikely to be asked to a white person, that is not because its racist its simply because they are clearly black. In the same way, one might expect someone in a wheelchair to be asked what happened, or someone with an unusual accent to be asked where they are from (white or not).
* The charity that the black person was from - Sistah Space - is that not racist? Look at how its spelt. Its a play on a pronunciation of a word that is only made by certain heritage of people with a particular accent type. So that also is racist.