"This has nothing to do with the race of the programmers.
.... so the AI can only treat it as English,"
It has *everything* to do with programmers: AI *does not know* anything the programmers didn't tell it.
What AI can do and what it can't do, is defined by the programmers. And only them.
"so the AI can only treat it as English, or let all racial slurs slide, because it could be AAE"
And programmers decided it won't do that. Definitely 100% based on *their own race*. No excuses allowed on this.