Were the Tamarians...
... racist because African American actors portrayed aliens whose speech is hard for the white characters to understand? Does it have insensitive connotations regarding African American Vernacular English (i.e., "ebonics")?
They didn't break rules. Their speech was metaphors -- HIGHER level talking. If i pointed to a couple and said "Romeo and Juliet", you'd know what i was trying to say. It wa shard for the whites (and everyone else) to understand because they weren't educated -- in the Tamaran history.
Or is it just that the Tamarians have sufficiently bumpy heads that the audience perceives them as "aliens" rather than "1940s tribal Africans in space"? The Tamarians, after all, do kidnap the white hero and force him into a knife fight.
They had more than bumpy heads -- they had full on make up.
Much different than even the Bajorans.
The Tamarians also had technology that was either equal to or perhaps superior than the Federation -- NOT primitive. And it was the Tamarian captain that initiated the relationship. It put a twist on the usual "Enterprise crew teaches other aliens what is right"
Now, if Darmok had taken the place of Code of Honor, and the characters were in fact black humans and not had the make-up, i think this episode would still be considered one of TNG's best by many (embodying Trek's theme), and we might have seen other episodes with human races that were made up of non-whites.