I agree that many people have different thoughts on this. I think it’s pretty easy to see major differences between, say, Zork I and 80 Days by Inkle, and to have a preference for one vs the other. (I personally enjoy both more than most graphical/controller based games, with a slight preference for Zork).
That said, this question comes up a lot, and I have a running list of each conversation as it happens. Here is a timetable of discussions of this question:
1996 (rec.arts.int-fiction)
Does int. fiction have to be a game?
1998 (rec.arts.int-fiction)
Are there any alternative to puzzles? (contrasts puzzle games with CYOA/branching)
1999 (rec.arts.int-fiction)
Defining IF (yet again) (was: Are there any IF+RPG?)
1999 (rec.arts.int-fiction)
What is IF?
2002 (rec.arts.int-fiction)
What is IF really?
2003 (rec.arts.int-fiction)
class on if (update)
2004
‘interactive fiction’, a meaningless signifier?
2005 (rec.arts.int-fiction)
Why newcomers struggle with IF.
2006 (rec.arts.int-fiction)
Defining IF (again)
2008
Communicating the type of game to the player
2009
CYOA trend
2010
Emily Short – Down with Parsers!
2011
What is CYOA as opposed to IF
2012
Surprising conclusion: CYOA is not MCA!
IF and Choice (or, another goddamn CYOA thread)
2013
Something I noticed
IFcomp is gone all hail IFComp
2014
On the overwhelming response to non-IFComp events
2015
Why are there so little parser games now?
2016
Why can’t i get into CYOA or restricted parser games?
2018
IFComp 2018 Reviews