Those aliens would also think all criminals are White, Most Doctors, especially the really good ones, are Black. Same for every other respected profession.
Every White cop has to have a no nonsense Black boss to keep him in line.
In fact all people in charge are Black or if there are Whites, the Blacks are over the Whites. and I have seen this one several times: The White Doctor and Black Doctor disagree on treatment. The White patient chooses the White Dr. which turns out to be really wrong.
There was one show, I actually liked but it got funny it was so ridiculous. Every Psychiatrist at least the good ones were Black. Almost every scientist was Black, again the top ones usually Black.
The show is Smallville and Superman’s best friend is Pete Ross who is Black. Well he was White in the comic books. Unfortunately the actor playing Pete Ross got caught selling drugs and went to prison so they had to write him out.
They do throw in a few Chinese or Japanese just to show they are not prejudiced, at least against them.
All this in a state, Kansas, which is 2% Black.