I disagree. I see the same false compromises on both sides.
In your example of the dragonborn. We have three options, "No, play something else," "I must play a dragonborn" or some compromise. This is really straight forward.
First we start with "play something else." That isn't a compromise as is. Neither is "I must be allowed to play a dragonborn." Both require complete capitulation. Same with "Let me play a tortle and this is how you can include them in your world," and "Play an approved race and Ill make the game fun." It's false compromises all the way down. All of these require copitulation.
Your example, "you can come from the Dragon Clan of barbarians and call yourself a 'dragonborn'" is a compromise. It is giving something, the word Dragonborn. It is a DM favored compromise, sure. But it is a compromise under the definition of the word. It's a compromise many players would take, in my experience.
Another compromise might be "you can have scales on your skin, but you'll be called human or elf." A third might be a lizard-man with dragonborn mechanics. Each of these are somewhere on the spectrum of compromises. Each has both sides giving something and getting something.
Looking back on this thread, I see none of these compromises, nothing close. Everything is either A or B. It's either "tortle" or "no tortle." No discussion as to how to give someone what they want from the tortle, while keeping the worldbuilding intact. Nope. No discussion that we should have the discussion at all, that talking is required. Nope. Nothing.
If people wanted to compromise, the answer to the question "Why do you want to play that?" wouldn't be "I just do, or I walk." And the answer to "Can I play a Tortle? Wouldnt be "No, its not on the approved race list, take a walk!" Both are simply demands of copitulation.
So no. All I see is a binary. A binary presented while screaming the word "compromise." A binary each side has now told me isn't a binary.
I think the better way to approach the situation is to ask the other side "Whats important to you," and start from there. The answer will tell you if a true compromise is even possible.