I call bull.
I can learn from a math teacher in an hour what would take me possibly years, or a lifetime for that matter, to discover on my own.
During 2 years of college lecture classes one can learn what took philosophers and eventually mathematicians nearly 2000 years to discover.
But what about the arts?
Again, same story. Thousands of years of progress and theory can be summed up and taught in just months. (A wee bit of practice may then be required to master certain skills! ;) )
Yes some self directed learning is valuable, and indeed almost every class I took had aspect of self guided learning in it. Teachers loved leading us halfway to the goal, pointing us in a general direction, and then letting us go forth and discover the answer for ourselves.
Now do I think how public schools are currently ran is ideal? Heck no, far from it. No Child Left Behind was a huge damaging blow to the American educational system.
But what I always wanted out of school was more direction, not less. I passionately hated assignments where students had to go off and make their own video presentations and other such activities.
Yet in theory, giving presentations is of some value, it requires the students to acquire information on their own, summarize it into a communicable form, and then share that information with others. (I just despised how much class time was devoted to watching very bad presentations...)
But hey, that sounds like self guided learning, at a public school no less!
One thing to remember is that trying to dictate any one educational style is going to fail some non-trivial percent of students.
As I said in another comment, I did horrible in unstructured classes. More structure would have been my desire. IMHO school would have benefited from having 2 hours set aside just for an open study room for students to do HW in. But that is mostly because as a kid, left to my own devices, I would go home and play games rather than study. Heck I'd read a month's worth of reading assignments on the bus home, then never do the book reports!
Likewise for finding study groups. As someone with social anxiety (which was much worse as a kid!) asking the class to form groups would result in me hiding in a corner somewhere. Suffice to say I never was good at getting language practice in either!
But lab classes, oh wow I rocked at those. Love'd them. On a related note, questions come up as to the suitability of unstructured learning for certain topics. E.g. How would unstructured learning have students do genetic modifications of bacteria? Or play with explosives? Both are some of my fondest memories from high school! Both involved very explicit step by step instructions written down that we followed to the letter! (For good reason!)
I guess my overall point is that ideologues of any type tend to have a drum and enjoy beating it, much to the determent of someone somewhere else.