Thanks @cpradio for your comment and nice information.Yes, an IDE can surely serve as a text editor, but, as you know, it can also do much more, like compiling code, running code, …etc.
There are situations where you just simply need only a text editor, and there are others where you want to go beyond that, to using an IDE.
Most of whom I interviewed, including Yukihiro Matusmoto (Matz) and David Heinemeier Hansson (DHH) replied with one or more of the editors listed above, provided that I didn’t ask them to choose from certain editors, rather, the question was an open question. Even the small portion that replied with RubyMine for instance, when asked that the goal of the interview is about a text editor and not an IDE, the next reply sent from them was a text editor of their choice.
So, it appeared to me that the community seems to be aware of this distinction between a text editor and an IDE.
Does that make sense?