Often times in universities and a variety of fields I'll see a curriculum in which students are taught how to use super sophisticated tools or systems before using simpler ones; for example, students may be taught how to program in C++ before basic C or Python or taught to use professional software without hand-holding before simpler ones with hand-holding.
This is the equivalent of teaching someone to swim or float at the deep end of a pool first. Sure, you may have safeguards like holding onto the rim or an instructor keeping eyes on you, but what happens if someone messes up something and starts to drown in the pool? What happens when the instructor is gone? People may be scared of such a situation, and as a result, they won't be as willing to experiment or take as many risks out of fear. People will likely never learn how to swim without constant guidance and an instructor that's there to help them up when they fail.
Consider, for example, a language such as C or C++. A solid professor will instill into their students to use the right C functions and modern C++ safety features to ensure proper bounds checking and prevent memory leaks (which is unfortunately rare, in my opinion); however, it's still surprisingly easy for someone to forget to use the right functions and features, especially when there's more than one way of doing any individual thing. It also doesn't help that C and C++ do not have easy to understand error reports that tell you where you make mistakes. My point is this - without that solid professor around, it's much easier to mess up and drown in your own C++ code, not knowing how to fix your problems. Thus, students are discouraged from going out of their way to learn more.
I want to make it clear, I don't mean to bash on "the deep end of the pool"; it is often much more powerful and freeing than "the shallow end". I just mean to say that some people have a hard time learning and thriving in that environment. For those individuals, exposing them to the fears of drowning may not be the best strategy of teaching, especially when you could just be doing it at the shallower end of the pool first; you'll ultimately just end up scaring people off too fast instead of getting them curious to learn and to understand, so that eventually they'll want to dive deeper out of boredom from the shallow end, and will have the knowledge of how to do so. Or, maybe they'll be comfortable where they are and learn more there instead, and that can be okay too.