For some reason every conversation about this simple rule gets way too toxic
There’s definitely some additional nuance (like a pronouns in bio/username situation) but this should cover the broad needs of anyone who is approaching this with good faith.
My solution, get rid of gendered pronouns. Make “He/Him” gender neutral and get rid of all others. Why do I need to know the gender of a coworker I have only ever talked to in email? And why, when referring to this person, do I need to let everybody else know that I know their gender by using the correct pronoun? It’s dumb and pointless.
It’s like when I was a kid and it was very important that we knew which teachers were married and which weren’t so we could use “Ms” or “Mrs”. It’s irrelevant to every conversation.
It was Miss for unmarried women before Ms was coined and popularised for "none of your business whether I'm married or not" so Ms was acceptable regardless
Doesn't Mrs look like it's missing a possessive apostrophe, a Mr's woman?
And your main point, degender the male pronouns, it wouldn't work. "Man" used to mean people, male men and female men and child men – boys and girls – had different words, some of which are still around. That's why people say there's nothing gendered in "chairman" (which 50 years ago was logically equal to "chairperson", unless you count other species as people).
I actually prefer it as the neutral singular, but everyone decided that was dehumanizing. To me it feels natural because if you don't know an animal's or a baby's gender, you call it it.
People didn’t so much “decide” that, as it was used that way by bigots specifically because it was historically only used for animals and objects. They used it as a slur to hurt folks in our community, and like any attempt to reclaim a slur, even though the reclamation is an act of power, there are going to be people who were targetted by the slur who struggle with the concept of reclamation.