This is not intended to single Dire Bare out, but I think it is a good illustration of how systemic inequality actually functions.
Access to particular individuals, especially in informal settings, is a huge advantage.
In an institution that does not prioritize equity in hiring practices, casual interactions in a restroom with a superior, might make all the difference for a promotion, for example.
People feel comfortable with what they see on a daily basis, and this, can lead to real world equity issues.
If Joe and Vince Vaughn, are just handed roles in the Weiss helmed Star Wars movie, then the game goes from a “Mostly Harmless” rating in the Hitchhiker’s Guide to the Galaxy, to:
“Most definitely harmful”.
From a D&D perspective, the fact that most of the D&D creative staff is White Male Americans is troubling.
It's okay, I don't mind.
If D.B. Weiss and David Benioff produced a new TV series starring Joe Manganiello, George Finn, Paul Wight, Taran Killam, and Vince Vaughn with a soundtrack by Tom Morello, directed by Kyle Newman, written by John Cassel, with actors trained by Ron Matthews . . . . okay, I'm getting a bit ridiculous here . . . . if a creative project came out of Joe's weekly home game . . . I'm okay with that. It's not institutional inequity, it would be friends choosing to work together on a creative project.
Now, if Weiss and Benioff cast Manganiello in their next project, not because he's best for the role, but because they want that +10 sword of weasel slaying in the weekly D&D campaign . . . . that would be problematic. Even moreso if it did become institutional, if this sort of thing happened all the time.
"Who you know" and friends choosing to work with friends has long been a part of how social networks have worked, and it isn't inherently unethical or inequitable. When it excludes classes of people and becomes institutionalized, that's a problem . . . but that is not what we are dealing with here.
What do you people want? For Joe to announce, "Due to points raised on the internet, I realize that my home D&D game with my friends, who also happen to be successful entertainment celebrities, is inequitable to those who can't play in my weekly home game. So, I will no longer play D&D unless it is a corporate or charitable sponsored event with equal access and players to be chosen by lottery."
Now your last point, that the D&D creative team is mostly (but not all) white dudes . . . I would say that is an issue, it is concerning (although, not "troubling"). It's an issue WotC is aware of and has begun to take steps to correct. Okay. What does that have to do with Joe Manganiello's home D&D game? Nada.