Edit: commenter below links to Tom Lehrer's New Math, and yeah the crap they made me do in math class ("write a paragraph reflecting on what you learned about multiplication") is also an instance of this 60s reaction against rigorously and uncritically learning foundational material so you can do meaningful critical thought once you've mastered the basics.
Yeah. This was the cognitive revolution after a long period of (excessive, imho) behaviorism.
The pendulum swang too far in the other direction in some cases.
Shockingly, this has come back into style. My brother's high school math classes have been of this type for the past couple of years.