I've been looking at some job postings and noticed that a fair amount of them list IDEs under the 'required skills' section, even for senior positions. This is not localized to one company either, but rather it's something that comes up once in every few postings.

I am perplexed by this job requirement, as my mentors and some of the best coders I've seen in my life were VIM/Emacs ninjas. Similarly, when I work with people I don't much care what tools they use as long as they are productive on the team.

Can someone please explain the rationale behind hiring managers making IDEs an official job requirement?