I don't get why it's a good argument to say that something exists for hundreds of years. Thinking about flat earth was also thought for hundreds of years.
And round even longer :)
I didn't say it's a good argument to keep things that way, I meant to say that the naming itself doesn't mean women are excluded. A gentlemen's agreement is a well-understood term, and if you start saying something gender-neutral such as "gentleperson's agreement", you may sound more inclusive, but you're also less likely to be understood, especially by non-native-speakers.
"Can we have a gentleman's agreement to" -> "Can we agree to"
Fewer words. Well understood. Any inclusivity issues? Ah, the life of an editor.
For the record, my post was not an effort for social equity. It was English golfing. I'm sure there are better golfers.
The big dispute was about whether the earth was at the centre of the universe; heliocentrism was contradicting the church's doctrine at the time. Somehow this ended up in popular culture as an argument about the earth being flat which it never was.
Now of course, it's entirely possible that earlier cultures, before the Greeks, were under the impression the world was round... or any other shape.
Though, change to languages are opposed and pushed for political reasons so it's no surprise to form an argument that relies on age of something to justify it similarly how people need political atmosphere to justify the change instead of solely arguing on the basis of descriptiveness or clarification.