It's also a myth that devs choose NoSQL over SQL because "SQL is too hard."
What I see more of is situations where the developers "know" SQL but still just don't want to sit down and figure out their data models.
It's like, the temptation to reach for the nearest short-cut -- whether that means over-reliance on ORMs (or hodgepodge 'data access layers'); or continually munging stuff at the application layer for nearly every operation; or... Mongo -- is always just too great.