IME, it's because when you view vim as just another element in a list of "things that let me write code into files", where sibling elements are "IntelliJ", "vscode(ium)", etc, then vim comes off as looking like "gedit but with keyboard shortcuts and no discoverability, oh but you can research and install and configure a million plugins with no overarching design cohesion and you also have to maintain and update them". As opposed to many other editors/IDEs that are designed holistically and more intentionally, and have a much higher "just works" and discoverability factor.

From that angle, yeah, it's probably fair for people to look at vim and go "what even is this".

I think the right way to look at vim is "it's a powerful editor that is installed on almost every linux box everywhere that is deeply customizable and extremely flexible".

Seldom a week goes by where I'm not ending some ridiculous shell pipeline incantation with "| vim -" to dump it into vim and then do further investigation there (with regex, find/replace, etc etc support).

So, I consider myself a vim fan, but I don't use it for day-to-day coding but I still consider it an important tool in my toolbox.

I do think there's a crowd, too, for whom customizability for the pure sake of customizing is a big feature. And that's fair too. But I think that really tends toward being for amusement rather than productivity gains. Which is fine! Lots of software is for having fun, and having fun adjacent to being productive and make it easier to be productive. So I'm really not bashing anyone here, promise!