"The number could theoretically be billions" is internet catastrophizing that doesn't hold up in meatspace. There's millions of different names out there in the world but you aren't expected to memorize them all, so why that bizarre standard for pronouns? Just how many different people to you talk about with others in the third person?
I take it from the fact you chose probably the least important part of that post to address that you don't have a reasonable argument to the meat of the argument?
Well now you've pissed off the "they aren't people, they're women" brigade
So you would also complain about the use of "police officer" or "chairperson" instead of "policeman / -woman" and "chairman / -woman"? We are already busy degendering lots of language, why not pronouns too? The problem of misgendering and implicit gender bias is inherently ended by removing gender as part of the description / definition.
Look, if we're gonna laughably attempt to standardize the English language, white people spelling names badly changes first, followed by standardizing double last names. I don't tend to use pronouns on databases
Names are not common nouns, they are "unique" (allowances, obviously, that some people do have the same name) identifiers.
Secondly, standardisation happens whether we like it or not. There is a way to spell "ladder": it's not really forced - there is no absolute authority dictating it must be that way - but nevertheless there is form recognised as right so that everyone knows how to express two parallel struts connected by perpendicular rungs that you use to travel up and down.
Pronouns are not unique identifiers, and an attempt to force them into becoming one is almost guaranteed to fail. Standardisation is going to happen to neopronouns too: they can exist, and they will be whittled down to a limited number, because if enough people seriously try to make everyone hold to unique pronouns, they're going to end up running smack bang into the mass of people and organisations who don't have time to cater for narcissistic bullshit.