Whilst I can't stand either -- I have a great distaste for emacs -- the use of simpler editors is easy to understand if you know what the hell you are doing.
Honestly, MOST of the features of IDE's just get in my damned way! Code folding more often than not just hides bugs or prevents you from seeing the whole picture, IDE's often restrict you to a single window for each set of code defeating the point of large high resolution displays and/or multiple displays, auto-completion you end up wasting more time correcting than having it help you, etc, etc.
.. and more often than not their UI wastes endless pointless amounts of screen space on "code management" tools or stupid side panels and toolbars that would be better devoted to just "SHOW ME THE DAMNED CODE!!!"
But I'm a bit of an extremist on this count, since I find even colour syntax highlighting to be a drawback since it's an illegibly useless acid trip doing NOTHING of value for me as a programmer. I hated it the first time I saw it in Turbo Pascal 4 back in the '80's, and my opinion of it has only gone downhill as the decades have passed!
Clean simple lightweight tools that let you have multiple windows open side-by-side (well written code is usually taller than it is wider anyways, leverage that huffing widescreen or multiple displays!), with nothing that gets in the damned way of reading the code or GOD FORBID writing it.
Like a great many things these days there is so much incompetent GARBAGE being touted as "easier" or "helpful" or "being more productive" that's more echo-chamber cultist hoodoo-voodoo than fact. Fancy IDE's, RAD's, and so forth squarely fall into that classification for me as a developer. It's ALMOST as mind-numbingly idiotic as using a WYSIWYG to build a website!
If you can't program productively using just a flat editor with the most basic of features and HAVE to rely on a tool to handle the simplest of tasks, you're probably a really bad developer!
win32pad, editplus, notepad++, flo's notepad2 (what I use), sublime, vi, vim... clean simple doesn't get in the damned way. Anything fancier is typically just covering up for incompetence.
SO many times I've ended up in workplaces that "required" you use whatever pet IDE their project lead had a boner for at the time, and I always ended up screaming at the display "FOR *** SAKE JUST LET ME SEE ALL THE CODE AND EDIT IT!!!"
Of course with so many today just blindly copypasting other people's work together and going "wah wah, I don't wanna type" every five minutes with the TLDR twitter generation mouth-breather mentality, it's not surprising that IDE's exist or there are fools that buy into their lies.