This happened:
To Adams' credit, the continuing storyline of Dave the Black Engineer does suggest that he might be fucking with the boss as a way of poking fun at elite white people who tokenize diversity to make themselves feel better — which is definitely well-deserving of ridicule. I'm not convinced that Adams knows how to make that cutting satire in any way that's meaningful. Case-in-point: the trans joke that kicks off the drama.
In response to criticism, Adams insisted that it's not "about trans" and that the backlash to him only having one Black character is exactly why he hasn't introduced a Black character before this. Somehow, it never occurred to him to just … have a Black character who works in the office with the other characters, without making his introduction and entire subsequent existence based around the token-ness of his race — which is, ironically, what Adams depicts the boss as doing to Dave the Engineer.
Also ironic is the fact that the joke of Dave's racial identity (because of course his Blackness is treating as nothing but a joke) is completely lost in newspapers that syndicate the comic strip in black and white:
Supposedly, some of these newspapers have caught the problem and started publishing older Dilbert strips to get around it. Of course Adams would have known this was going to happen to some degree — which makes the bad faith trolling of the whole idea even more petty and frustrating.