Gosh I hate sloppy logic.
In Django Unchained, was it a racist decision that Jamie Foxx played the ex-slave while Leonardo DiCaprio played the plantation owner?
It certainly wasn't color blind - the actors were obviously cast in their respective roles based on their skin color. But sometimes, certain stories are arguably better served when certain parts are played by actors with certain physical characteristics. And in such cases, I think such choices can be made without implying any sort of racial tribalism or prejudice)
That said, this author has artistic license to tell his own story however he wants to, so it's a losing battle for anyone to claim that any character needs to look a certain way. And in that context, it does seem likely that many people who disliked the choice of actor may have had some white tribalist motivations.
But the author's argument that any preference for an actor's skin color automatically implies racial tribalism or prejudice is flawed. And flawed logic is a terrible thing. Because logic is how we communicate. And humans have an exactly zero percent chance of ever getting along with each other if we can't learn to communicate clearly.
All that said, kudos to Leah Jeffries for landing the role. I'm sure she'll do great.