In a semi-related issue, it’s beyond illogical and plain idiotic for a non-binary
to claim to be they/them, a pronoun used to refer to two or more people.
I realize there is no explanation for sheer crazy.
It's more than that. They are adopting the old linguistic concept: the plurality of majesty. It's why since the Bible was translated to Latin in AD 4th century, the book of Genesis refers to God with plural pronouns during creation "Let US make man in OUR image." Back when Jerome translated the Latin Vulgate, the norm at the time was to use plural pronouns for really respected authority, like either the current emperor or a past emperor still very much respected (like a lot of people here on FR still respect Reagan or Coolidge). So, he used plural pronouns for God when translating the Genesis creation story. That tradition has stuck in our English translations. And it's only in reference to God and only in the creation story of Genesis.
When a do-do head demands we use plural pronouns for him, he's demanding we treat him with the same majesty only God is treated with.
Sheer crazy indeed some things doctors can’t cure.