The Overlord wrote:
No, its because the Ligonians were presented in "1940s African Tribal Style" in that episode.
We covered this back in August in this thread
. The culture in the script is stereotyped, but they're Orientalist stereotypes rather than African ones; the episode explicitly says that the Ligonian culture resembles Ming China. The screenwriters based the Ligonians on samurai culture and intended them to be reptilian, or at least played by actors of multiple ethnicities. But the decision was made to cast them as all-black and use stock African accents.
So with a bigger budget, it would have been lizards, and then it wouldn't have been racist.