> There's another genre also commonly called Black Comedy where Black is African American not Dark.

Ah, well, that would explain it. I'm not American. I have never before now heard the term "black comedy" refer to comedy solely by African Americans.

That’s not true in colloquial American English. Movies like “Friday” or “Madea Goes to Jail” are just referred to as “Comedy”.

That doesn't contradict the person you're replying to

Black comedy has always been used to refer to a certain type of dark humour.

You need more than a few "Twitter critics on a righteous circlejerk" to change its meaning.

My context isn't Twitter but like Airline in-flight movie catalogs which had "Black Comedies" and it was movies with all-black casts rather than what I expected.

I’ve never heard “Black Comedy” used to describe comedies by black filmmakers.

However, I have heard name collisions with “Black Arts.” My city hosts an annual event called the “Black Arts Festival” and when I first saw the banners around town, I was confused. I learned the true purpose and have always wondered if some evil wizards mistakenly attend.