Me pronouns be dey/dem

Has it ever been explained why we need two of them? Like, why don't just "he" or "they" suffice, why do we need "he/him" and "they/them"? Are there certain people who identify as one gender in the nominative, but another gender in the dative/accusative form? If so, can we send those people to Mars, please?

Don’t feed the pidgins.

Trans female gets triggered after being called the wrong pronoun @ Alamo Car Rental

I prefer to make no pronouncement for the time being.

Oh, honey... your pronouns should be troll/it.

R3 that tranny sounds like a real blast to around.

Da man keep tryin' tah sond SMAHRT. Im' pontifikeetin'..

We'ah ti-yahd of Ooh-pee an' iz stoopid steetmunts! Im sey "dey" a lot, and don't follow up wid' nuttin'. Tha manz ah' FOOL.

I'm sorry, but I can't take this shit seriously. Fortunately, I've yet to be confronted with a situation irl but I work in a semi-woke environment (academia).