The first reason why I won't refer to individuals like Ezra Miller by they/them pronouns is because, from me, it would be a lie. I do not believe that any individual human being falls into a they/them category.
Why is it still a lie for me when so many people are capitulating?
Well, frankly, it's because your arguments as to why I should believe the words that you want to hear come out of my mouth range from bullshit to non-existent.
Really, most of the arguments are non-existent. You're just telling me that it's polite so I should say it. That's crap. We're impolite to people all the time and we make people uncomfortable all the time. Really, this is what political correctness really is -- it's goading people into lying and cloaking it with politeness.
When people make arguments, they're bad ones.
One argument is that there's been a singular "they" forever.
Yeah, that's true. We use that in sentences like "Everyone needs to turn in their homework." That's technically wrong because "everyone" is a singular antecedent and the sentence should be, "Everyone needs to turn in his or her homework."
Still, how do you not see the difference between this and saying, "Sarah started their car."?
"Everyone", despite being singular, implies a reference to multiple people in common language. This is a natural evolution of the language that people use plural pronouns to refer to "everyone." Similarly, it seems that a majority of people falsely use the word "data" in the singular. "Data" (outside of Lt. Commander Data) is the plural of "datum"; but, most people can graduate college without knowing that the word "datum" exists; so, a lot of people treat "data" as singular.
The only way that a person says, "Sarah started their car." or, "Ezra got arrested because they choked another woman." is if the speaker or writer of the words was informed of what the person wanted to be referred to and capitulated. Namely, it's language by order, which is authoritarian, rather than language by emergent order, which is how language really functions.
The other bad argument is that other cultures have several genders and therefore we should just view non-binary or non-conforming as genders in and of themselves.
Well, this really cuts to the bone of the issue.
Those other cultures had/have different languages. There were/are different names for the different genders.
This is where it drives me nuts about mostly cis and hetero people who consider themselves "woke" conflating trans and non-binary.
Trans people, no matter where you stand, give you a positive identity. "I am this."
Saying, "I'm non-...whatever..." is only to say "I am not..." and never to say what you are.
We all come to places in our lives when people are trying to plug us into one group or another and we don't fit. My whole four years in DC were spent with people trying to figure out whether I was a Democrat or a Republican. Since I was neither, I guess I was politically non-binary or non-conforming; but, that tells you very little about what I'm for or what I am. So, we have words and terms like "anarcho-capitalist" and "libertarian" which describe what I actually am.
The authoritarian side of politics has relished in language that deals only in negatives and word games.
Think about Antifa. "Well, we're anti-fascist. If you're against us you're anti-anti-fascist. That would make you fascist." Bullshit, tell us what you're for. Tell us what you are rather than what you're not. You're anti-racist? Great, so am I. What the fuck are you for?
None of this means anything if all we're getting from you is "I am not..."
Okay, maybe there isn't a word to describe your gender identity right now. Nobody is saying that neologisms can't exist. We come up with new words all the time. Some people are putting in the effort. It's just that you're not.
You just read Orwell as a handbook rather than a cautionary text.