I saw an admin created a poll about Ze/Zir and that the preference was to move to They/Them. I understand that is what most people expect in non-binary pronouns. However, we picked Ze/Zir intentionally when we added non-binary options, due to specificity and the confusing nature of the way the MOO handled pronoun subbing when we tried to make they/them work.
Ze/Zir maps in a similar fashion to he/she/him/her/etc which is what the MOO supports at a core level for pronoun subbing. They/them does not. Here's what I mean:
%S is standing over there -> He is standing over there.
%S is standing over there -> She is standing over there.
%S is standing over there -> Ze is standing over there.
%S is standing over there -> They is standing over there.
They/them lacks that specificity. At its core, the MOO was designed to support a bunch of different pronoun types, but the thing they all have in common is that specificity.
In real life, we might automatically swap 'They' for '[name] is standing over there.' to maintain the specificity and grammar of what we're saying. The MOO doesn't know how or when to do that.
I did some pretty extensive testing when we were adding non-binary pronouns and just couldn't get it to work. There were a lot of situations where using they/them worked just fine, but equally as many where it was confusing, vague, or grammatically incorrect because of how pronoun subbing works across clothing, messages, etc.
So, that's why we have Ze/Zir, and why They/Them is not the direction we went.
