Naughty blackface in Britain

The shrieks over blackface makeup never seem to end:

"A white actor "blacked-up" to play an African government official in a role-play exercise staged by the elite squad leading the fight against organised crime, The Times has learnt.

The incident, which has led to accusations of crass racism, occurred in a recruitment process for candidates applying to be overseas liaison officers for the Serious Organised Crime Agency (Soca).

A high-level internal investigation into the racism claims is under way. The allegation involving Soca - which boasts on its website that it "fully embraces the principles of diversity" - is the latest in a series of race rows threatening to engulf police and law enforcement agencies.

Source

Why can a white man not pretend to be a black man if he wants to? Is blackness sacred? If so that sure sounds like racism.