I'd love to see more people express some genuine opinions on this topic. It's something I think about a lot. I've come to feel like there's several main facets to this question: (apologies in advance for the long rambling response)
1) What is a "diverse cast"?
Should every character have a different ethnicity, gender and sexuality for a cast to be truly "diverse"? If they're all members of the same minority group, is that "diverse" enough to count, simply because they aren't members of the majority group we're contrasting against? If they're only belong to a minority group in some ways, but are members of a majority group in others, is it "diverse"? What if most of the characters in a cast belong to majority groups in just about every way, but one or two don't- is that "diverse"?
I could keep going, but I think you see my point.
2) In so far as all aspects of storytelling serve some kind of purpose, what is the purpose of a "diverse cast"? Does it really need to be justified?
Yes, I also roll my eyes when someone claims a particular character belonging to a minority group is "unrealistic" because their presence needs to be somehow "justified" in order to be believable.
But if the marker of whole cast being described as diverse is that it runs an international gamut of ethnicity and race, a full spectrum of sexuality and gender, disability, body type, and so on- let's be frank. How many people actually surround themselves with this kind of social circle? If the author has lived in a small rural town all their lives, it may be hard enough even satisfying the first requirement. So yes, I believe that, in some sense, a "diverse cast" does require justification.
For example: the circumstances of my life have placed me in a position where I have at least as many queer, transgender friends as I do cisgender and/or straight ones. But how many people who aren't also queer and transgender, and have lived for a time in a bustling metropolis, can genuinely make that claim?
if I were to write a story about myself, most of the people I interact with on a daily basis, whether it's for work, buying groceries, taking a walk, going to a movie, you name it- are going to be straight, cisgender people (they are the majority, after all!) If I were to read a story about a straight person going through their daily life in a small town in northern Ontario and somehow encountering nothing but queer people everywhere they go- in order to find it believable, I would require a justification.
My first thought wouldn't be "oh, what great representation!"
It would be "what the hell is going on here?"
If the protagonist were queer themselves, I might be more inclined to believe they'd seek out other queer people, or be in the know about a local scene. But if not? I wouldn't be surprised if they met one, maybe two people they acknowledged to be queer in their entire lives, let alone transgender. So minus a plot-relevant explanation, this kind representation in a real world setting would feel extremely forced.
But alright, let's say you're in a big city, and you're surrounded by diversity on every corner- in theory, there should be no excuse for not having that diverse cast now, right? Well, actually...
Another example: I lived in an immigrant ghetto in a massive apartment complex with other people of similar ethno-religious background and financial status to myself for years. The people who lived there mostly interacted with others of the same community. They spoke many of the same languages (or at least mutually understandable ones), shared religious and cultural observances with their neighbours, and dealt with similar problems in their lives. There are many reasons why we stuck together and rarely ventured outside our community for finding work and doing groceries, let alone friendship. And I left that community for a reason too. This is a common enough story.
So there are a lot of reasons why "diverse casts" may not form organically in the real world, even when the opportunity is seemingly there. The wealthy seldom associate with the poor. People gravitate to others who share their beliefs and experiences. Customs, traditions, religious observances- these things all bring people together- but they can also foster an in-group out-group mentality. Gendered roles and expectation divide friend groups all the time. And then there’s all sorts of bigotry and systemic issues that can drive a wedge between people of different backgrounds and life experiences- even if they’re sitting in the same room and have “every opportunity” to make friends.
In order for people to actually foster diversity in their lives, there often needs to be an external inciting incident. Going out of town to college. Joining the military. Maybe even just having a rare hobby. Anything that thrusts them into a situation where they are forced to cooperate with vastly different people in some way and form genuine, lasting relationships with them.
So in that sense, I do believe a justification of sorts is necessary in any fictionalized real-world setting.
It doesn’t even take much to acknowledge that yes, it’s a reality that real-life examples of a group of friends that look like an urban community centre advertisement (or at least the ones I’ve been involved in making) are few and far between- but here in our story, these people all have a reason they know each other.
Failing that, I believe a slice-of-life story can seem to have “forced diversity”. Because it’s not just about representing the individual people in a sympathetic and believable way. It’s about the circumstances surrounding them too.
3) Okay, but what about fantasy settings? Real-world rules need not apply, right?
Yes and no? If your fantasy world involves fictional ethnic groups with different beliefs, traditions, histories and so on, the same idea applies. If it involves any group with a history of marginalization, the same idea applies. For those groups.
But you might render real-world perceptions of race on the basis of appearance irrelevant. (to quote Terry Pratchett about his Discworld books, “Black and white lived in perfect harmony and ganged up on green.”) Same-gender relationships might be completely unremarkable. Maybe you’re writing about a species that doesn’t even have a concept of gender, or magically-induced disabilities that have no real-world equivalent.
So in the context of fantasy and certain kinds of sci fi, I’d argue there’s no such thing as “forced diversity”, unless you are going out of your way to replicate real-world divisions between people.
4) How far does your definition of a “diverse cast” extend?
In a visual medium like comics, where you may have no choice but to depict every single character, no matter how minor-I think it kind of begs the question. How do you treat crowd scenes? Random extras who may only appear for a panel or two? Depending on your style, they may need to be rendered with enough detail for readers to discern parallels to real-world minority groups, or lack thereof. Does the definition of a “diverse cast” extend into that too? And if every panel with background characters should have an unspoken quota of representation to meet the requirements of a truly “diverse cast”, what would make it diverse enough?
I have no hard answer for that one, personally. Just intuition.
And finally, I feel like there’s a lot to be said about all the nitpicking that goes on with “diverse” characters (it really bothers me when I see the word “diverse” being used to describe a single person, tbh) It’s not that I don’t believe there are legitimate reasons for holding characters who represent members of a historically marginalized group to a different standard. I do.
For instance, if I were reading a story where there is only one Jewish character ever introduced, and they just happen to be the caricature of a greedy banker- I don’t think it would unreasonable to wonder if the author might have Neo-Nazi/white supremacist sympathies.
But does that mean no story with a Jewish banker is ever okay- or that any fictional Jewish banker ever written must be represented as a paragon of virtue in order to avoid being perceived as anti-semitic? I know people who would respond to that question with “Yeah, absolutely!”- and I completely disagree with them (yes, I am Jewish, if you’re curious).
Why do I disagree? Because I think if we go around punishing even the remotest perceived suggestion of bigoted stereotypes in fiction for every minority group in existence, it makes for a culture of fear- and the ones who have the most to lose from it are minority creators themselves. We are the ones most likely to create fiction featuring people like us, and are also less likely to have access to the resources or popularity of non-minority creators. They may have their work scrutinized over problematic representation, have their reputation dragged through the mud, and lose a vocal part of their audience- which is no fun at all. But minority creators are more likely (no, not universally so, but often) to have their entire careers on the line over accusations of being “problematic”- especially if placing emphasis on creating characters like ourselves has already contributed to making our work more “niche”!