To shoot down the racism of South Africa in 1975 showed how ahead of their time the Goodies were, Yes there are terms used here that in 2019 are seen as unfortunate but contextually in the worlds of the Black & White Minstrels/ Love Thy neighbour etc this episode is radical.
None of the Goodies supported Racial attitudes (even Apart-height) this episode should be seen as showing how bloody stupid we humans are for finding reasons to create hate.
We really are a horrible race - why care about colour, sexuality, etc, etc ...