Actually, there is a way to decide if something is scientifically better. All you have to show is that your construct is competitive within the ecosystem of constructs. You can weakly improve upon an existing model by adding tons of domain-specific complications, which is what should've happened. But instead of saying that there are two predominant sexes, along with many abnormal and discrete bins, they propose a "continuum".
The researchers found that, in the most inclusive definitions, 1% of the population isn't sufficiently accounted for by traditional constructs.
But there's no new theory here. How do I predict complications based on what factors? What's the new model? The "spectrum"? A spectrum is a scale with escalating and deescalating values as you travel up and down, where jumps in the spectrum are connected to jumps in prediction. As for abnormal and discrete bins, well, the scientific community already has that. What's new to the table? A reformation of language so that we avoid the word "abnormal"? But where's the improved model?
Also note that you propose that there's no way to think about scientific or construct "betterness". Yes there is. You can measure by complexity, prediction, explanation, or generalizability. These are just a few ways. But you waved away scientific discussion, and instead choose only to use the moral lens, and bring up sociopathy.
Also, the reason I am talking about human limitations in processing large numbers is because I am accusing the opposition of abuse. I am not saying you should believe me because of X, I'm saying beware of opposition arguments because they are abusive to human minds.
And on the matter of using percentages to interpret numbers, I return to my example of state budgets, because that is a place where politicians often abuse psychology by stating what appears to be extravagant numbers. By extending your statements, I might say that not only is $70B a lot of money, but so is $7B. But then what if you told me that $70B is less than 1% of the state budget? What did you just do to that number?
Honestly, 10,000 people dying is a lot. Therefore, let's not talk about construct validity?