You're making the argument that black people shouldn't be able to enjoy HP Lovecraft's works.
Of course, Lovecraft Country, with black leads, was perhaps flipping a giant middle finger at HP's corpse.
The same would also apply to Wagner, but his association with "A Certain German Party" is fresher than HP's racism.
Who gives a shit what the author thinks, as long as it doesn't leak into the work itself? I can only speak for myself, but I've been a fan of this game for years and sunk a decent chunk of money into it. I want it to succeed. The only time the author's neuroses have been at all relevant are when they interfere with the development and quality of the game, which they have.
It's easier to separate the art from the artist when the artist is no longer around to make a profit from their work or use their fame to harm others (i.e. DEAD). HP Lovecraft, Richard Wagner, Robert E. Howard, Edgar Rice Burroughs, and the rest from the early 20th century are no longer here to stir up shit and vex us.
Living "Big Name" authors/artists, on the other hand, whether we're talking about JKR, "Ye," or others, do have the ability to use their money and influence to enable hate. Honestly, Selebus is not that influential outside of this small pond, his rage isn't really harming others that I can see, but money is energy, money is a transferrable form of our physical/intellectual labor. We all have to decide where we want our energy to go.