I agree, I half expected one of the crew to say: "The natives are getting restless."From Memory Alpha:In this episode, the entire humanoid population of the planet is portrayed by African-American performers. In the teleplay, however, only Lutan's guards were specifically written as being African.The director was fired over this, and Les Landau directed the rest of the episode uncredited.
And, according to you, they - the Ligonians - were unreasonable. So, being reasonable would mean they are not stereotypes? (They are a proud and strong race like many other alien races in Star Trek, just because they didn't kowtow to Picard and his crew doesn't make them bad).
The unreasonable part referred to abducting a woman, and refusing to hand over precious medicine (or whatever it was) unless they let them keep her. Stereotype referred to the clothing and drum-beating, etc, things you would see in movies from the 1940s. Not mutually inclusive. They were written as unreasonable and portrayed as stereotypes.
That would have completed the cliché.