Racial sensitivity has never been Who's strong suit
The series' first black character was problematic, to say the least. In 1967, black actor Roy Stewart was cast as a Cybermen helpmeet called Toberman, in Tomb of the Cybermen; in the script he was deaf, yet this detail was omitted from the final version. So what we ended up with is a largely mute, subservient black man - essentially, a slave. Then 10 years later, in the classic episode The Talons of Weng-Chieng, the Chinese characters were played largely by white actors in make-up, one of whom is given the line, 'I understand that we all look alike.' Oh dear.