I think this is a fair point, and I’m sure some of the objections to colour-blind (or gender-blind) casting do spring from people simply disliking the sense that inclusive politics are affecting what they see on their screens.
It’s just not the only reason people can find this worth discussing, that’s all. I don’t, personally, ‘object’ to it, at all, but I think it raises questions - because, unlike food choices and ahistorical clothing/decor etc, gender and ethnicity are intimately tied up with long-term structural power differentials that affect people’s lives to this day. Unlike the presence of the potato in the 1530s, these things still matter and are still live political issues.
So some of the discussion on these things can be motivated by racism or discomfort with representation, or wanting have have a go at ‘woke’ or whatever - absolutely - but it’s not the only reason some of us find this interesting to talk about.
Somone said earlier these things always devolve into an argument between authenticity and representation. I don’t think that’s quite right, because my argument is about how important it might be to have truthful representation (not just authenticity). I think the divide is between those of us who think the representation of material facts has a real and meaningful value, versus those who think that historical injustices can be (partially) addressed by a sort of fantastical collective effort of will, a construction of an imagined and more just past.