If no one else is breaking ranks, I will.
I couldn't care less about 'colour blind' casting if that is clearly the intention. The hair colour, skin colour, height and any other physical features become irrelevant to the actor's ability to get 'under the skin' of the character and give a convincing performance.
Sometimes casting will be done to challenge the audience to think more about the character(s) as with all male or all female casts, African Shakespeare or Western noh theatre.
Sometimes it makes no difference at all who is cast. The audience has no preconceptions and is not surprised.
Sometimes it is right to cast as closely as possible to the historic racial/gender/age profile of the character - but not always. It depends what the drama is trying to do and who is the audience.
FWIW I thought the black Anne Boleyn was good. After 10 minutes her skin colour became irrelevant - it was all about the tragedy and the court politics.