I have a theory regarding the purple and black: I don’t think it had anything at all to do with red/blue states, etc. I think she (and everybody on that stage) wore purple and black to symbolize the mourning they were feeling.
You know...like the bunting you see on the stationhouse when a fireman or policeman dies. Or the black or purple vestments traditionally worn by priests at a funeral Mass.
Regards,
Purple is also a sign of royalty. She thinks she’s special.