Is this personal taste, or has it to do with the scope of the projects these guys are working on?
For verbose languages, you can't beat auto-completion and auto-import.
And you can get both in vim, emacs, etc. The lines between those and full IDEs are blurry with the right (or wrong) amount of plugins.
There are many other advantages like out of the box support for a lot of common use cases like refactoring, navigation, build tool support, reuse common shortcuts like Control-C Control-V for copy-paste etc.
I would definitely advice new engineers coming into languages like Java to pick up an IDE like Intellij instead of vim.
I like how you can use command keys to quickly toggle on and off the project file and current-file's-components browsers, leaving the "distraction free" * editor window for much of your work.
* yeah, there's a mode with this name that auto-wacks ALL the supplemental panels, AND the window frame. I don't usually go that far, but it does show that they "get it" as far as what many of us IDE resisters disliked.