(but I still think this is on nginx more than emacs - unless they really mean foo~ and not .foo~ )
There are a ton of Emacs users, and it's doesn't make much sense to talk about them as a group like that, no more than if I were to say, "The list of things Windows users don't get..."
You can change your own defaults quite easily!
Changing the default setup with emacs that has been shipping for > 30 years is tough.
Getting nginx to ignore a well established pattern by a well established editor seems equally sensible and perhaps more doable. Yes?
I disagree about "tough". Emacs has changed for the better in new releases quite drastically in the last years in my experience.
(but I still think this is on nginx more than emacs - unless they really mean foo~ and not .foo~ )