This goes to the bone of the problem that the doc, and similar tools, is trying to address.
The scenario as described feels spot on to me, like this is the way a lot of games would go. The crestfallen looks, etc. And the point of inclusivity is that we can do better and should try harder to do better, because the priorities described there are upside-down.
I even get it. I mean, if I'm one of those players and my character's a were-rat I've gotten to 19th level and it's my favorite character of all time - and now it has to be a were-squid, or we have to roll up new characters and start a new campaign? I mean yeah, hellz yeah, I'd be super disappointed. Probably pretty irked, honestly. I'd see if the new player would be willing to wait a session or two so we can wrap things up or have one last big battle or such. But if that's not reasonably possible, if somehow we can't even agree to start a new game when this phobic person is available and play the old campaign when they aren't, why would I send them packing? I'm choosing a loved character over increasing my gaming group and the promise of never having to fight giant rats ever again? I mean, how is this even a choice? What kind of person chooses their character over the emotional welfare of this apparently keen human sitting across from them? Why would anyone think that's okay? Why would anyone thinking six people making that choice makes it okay?
In this scenario, the phobia of rats is being treated as qualitatively different from a person's race, gender identity, or sexual preference; these other attributes are considered reasonable things that define the boundaries and sensitivities of the new player (based on presumptions, not by querying the player), while the phobia is not. An additional point used is that complaints of misogynist content should be treated one way, while not wanting rats in a game because of real emotional distress can be dismissed if inconvenient. (And while I laud the notion that racist, misogynist, or most -ist content is inherently problematic and should be discouraged, if a group in someone's dining room is all down with it and enjoys it, well, that's not really what we're discussing here. We're discussing dissent and request for change for deep emotional reasons, not whether complete accord can be achieved on chain mail bikinis.)
The existing players here have decided that their happiness of this specific gaming experience is derived primarily from the specific game content, not the social aspect. Their happiness will be shattered should that content need to be substantially changed, or worse, exchanged for a new one. Their priority is the game, not the people who'd play it. That's not social. It might border on sociopathy: more value placed on an imaginary world than on real people? Yikes.
I mean, one can try to make this about numbers - 6 players want rats, one can't play if rats are there, 6 wins - but the core decision is that make-believe trumps humans. And that's just plain weird. And I'd argue it's plain bad. Wrong. Antisocial.
The unwillingness to accommodate the phobic on the grounds that players have "too much invested" in an long-standing elf game. The framing of current gaming goals and contentment of a few unempathetic souls as qualitatively more valuable and reasonable than including a willing gamer in the social experience and/or in ensuring that one person doesn't suffer avoidable real-world emotional distress. The fundamental premise is deeply troubling.
The "cost" of changing a campaign. Really. The "cost."
Celebrim, you try to turn around my "get out of my yard" rant as somehow the hypocritical face of my "side." But it ain't. You're arguing groups are reasonable in turning people away asking for accommodation for things they can't help (though probably would very much like to), excepting things you've predetermined as somehow "morally" okay to consider, like a physical disability, their race, etc. My rant is against people who choose to be unempathetic, who choose to value their elf game over the human who'd sit next to them. Apples and oranges, not pot and kettle. Inclusivity doesn't mean jerks are welcome. It doesn't mean disruptive players are welcome. It doesn't mean every point of view is welcome, especially when that point of view is that a player's phobias are grounds for dismissal. It means that people who are trying in good faith to enjoy a social game despite some very real and possibly deeply personal issue should be given the opportunity to do so, even if that means your make-believe character or make-believe world has to make-believe some room for them.
Anyone can explore an imaginary world, be an imagined character, any time they want - in their head, in their home, on a bus. They can play a solo RPG, whether P&P or video. They can write a story, a script, and have complete control over events and rules. But that's not what we do. We gather. So having decided it's better to share this experience with people, why is it troubling to folks when someone requests [X] be avoided? Why is that so threatening as a concept? How is an imaginary game so sancrosanct?
I've been mulling this since the thread started, and can't find it. Every answer I come up is basically a flavor of the social aspect for such folks being a means to an end, like for validation, attention, control, etc., and that the game is a proxy for their egos. I dunno. Choosing a game over a human - it's just not social.