Hi there, thehangarqueen! Cavegirl here, designer of dungeon bitches.
As you might have noticed, DB is a game about lesbians. This is its central core premise. As such, the protagonists of the game are going to be lesbians, because that's what the game is about.
This is a pretty basic level game design thing; the protagonists of your game are your player characters. You will notice a lot of games do this. In Lancer (a game about mech pilots), you are required to play a mech pilot. In Monsterhearts (a game about teenagers), you are required to play a teenager. In Don't Rest Your Head (a game about people with insomnia), you are required to play somebody with insomnia. In Pendragon (a game about arthurian knights), you are required to play an arthurian knight.
Dungeon Bitches is a game about lesbians. You are required to play as a lesbian. If you weren't, it would be a different game, about something else. Realistically, if you remove the lesbian bits of DB you get just yet another dark fantasy dungeon crawler and the world has plenty of them already.
So. The game is about lesbians. What does that mean?
My fellow creators and I found that, in practice, the most useful metric for that was the lesbian community, and - being a community - its boundaries are fuzzy. In the game, like in real life, we care less about strict taxonomic definitions and more about who's welcome (or *should* be welcome) in a space. So, rather than going with a strict dictionary definition of lesbian, we went for a 'good enough' definition, which includes space for bisexual women, ace women, and people whose gender identity might not strictly be 'binary woman' but who are close enough that they feel comfortable in these spaces.
Let's take bisexual women first. Personally, I am not a fan of biphobia in queer spaces, nor the whole gold-star thing, or any of that. I didn't want to write a game that pushed bisexual women out of the space it's there to represent.
Same with ace-spectrum women. You're gonna have trouble fitting into cishet society, so you're welcome into the community if you want to be. A decent amount of design work went into carving out a space for ace characters in the game.
So, let's get to the topic of non-binary people. Non-binary is not a single pinned-down identity. It covers agender people, bigender people, people whose gender varies, people whose gender is a third thing outside the regular binary, people whose gender is much like one of the binary genders but somewhat askew from it. There is a broad and complex world here. We had non binary people, of a variety of identities, on the design team and in our playtests, and designing space for these different identities.
So, the question, then, is "should non-binary people be part of lesbian spaces"? And I will be honest, the answer for me and the rest of the team is always going to be "it depends". Whether a given non-binary person is part of the lesbian community will depend on the gender and sexuality of that individual person. The position of the game is that it's a personal judgement call; somebody is in if they feel like they ought to be in, and not if they don't.
I'd like to think that this is followed through in the actual game itself; we use a wide variety of pronouns throughout the text, and our art likewise tries not to limit itself to only cis, binary womanhood in favour of a more expansive and inclusive vision of the game world.
Consider the other possibilities before us.
Perhaps we could state that the opinion of the game is that Dungeon Bitches is exclusively about binary gold-star lesbians. Anybody outside that little dotted line can fuck off. I think doing so would make the game weaker, make the themes it can explore less interesting, and would ideologically align it with movements I dislike.
Alternatively, perhaps we say that Dungeon Bitches can be about anybody, actually, and lesbianism has nothing to do with it. That would also make DB a far weaker game by immediately excising its central themes. Arguably, it wouldn't be dungeon bitches, it would just be another Dungeon World knockoff.
Both of these would be bad.
I think your central complaint is that Dungeon Bitches is, fundamentally, a game by, about, and for Lesbians. It takes a broad and impressionistic definition of who a lesbian is, but that's what it is. And you don't identify with being a Lesbian. You do not want to present yourself as such. That is your right! If you are not - by the game's expansive definition - a lesbian, then Dungeon Bitches is not by, for or about you.
Luckily, you do not have to play Dungeon Bitches. You can if you want to, of course. If you aren't a lesbian, you can still play Dungeon Bitches, because ttrpgs let you pretend to be other people. But if you don't want to do that, then you don't have to. You can simply accept that something has been written that is not catering to you, and move on with your life.
Heck, you could even write your own games that focus on the identities you do resonate with. I have, for example, been quietly yearning for somebody to make a genderflipped Dungeon Bitches about gay men (presumably it involves paisley shirts and mimosas), but I am not the right person to make that. If you want to see games in the world that explore the nuances of non-binary identity and your perspectives on them, then the best person to make those games is you.
Hell, if you did go out and make those games, I would not want you to dilute them thematically to better include me.