I suppose that she got natural grey hair despite she is quite young for this. It happens.
But i don't like and I'm free to my opinion. Shame is a heavy word not to be used in a discussion place. We are here to express our opinions, if someone could not bear this, just don't come.
Yes it is her natural, but the huge majority of people perform apply modifications to their natural appearance, hoping to appear better. She is a gorgeous woman but IMO grey does not suit her at her 50s. If course someone could have another opinion, we are all free to express it, no censure.