I think you have put quite a spin on what happened.But saying that one black person, who was obviously getting a lot of racist abuse, was not actually affected by racism, then when confronted on this by a black person, telling them that they are racist to suggest he is in no position to decide if a black person is suffering from racist abuse because he's white, is in itself racist.
Anyway - this is the 'black' woman who was said to be "getting a lot of racist abuse":
and this is the (according to you) black person who confronted Fox:
Calling these people black (apart from the fact that the woman looks to be more of Asian descent therefore not black according to the acronym BAME) - would seem to me to be racist itself.
Regarding Meghan, would anyone call a person white if the ancestor situation were reversed?