While I am a Mac user, I've used Vim a lot, so I don't want to make it sound too much like I demand text editors be visually stunning works of art. :) Code initially looked just kind of clunky and toylike to me, in a way that Atom -- and Mac native editors like TextMate and BBEdit -- didn't. It's a little hard to explain. Code still isn't my favorite editor, but it's probably my favorite cross-platform editor.
For me, it’s the noise and clutter — every time I spin it up, it feels like VS Code is demanding my attention in multiple popups, and there’s a new tab or button I’ve never seen before with some mystical purpose, and the bottom bar is some jarring color that makes me feel like something is broken.
IntelliJ IDEs feel similar — sometimes I’ll open them up and after upgrading several plugins and dismissing a bunch of popups and “what’s new” dialogs, I don’t even remember what I was trying to do in the first place.