It's pretty hard to learn something just by reading. It takes doing. That's where you get stuck in someone else's mindset.
In fact, reading what somebody did will often help you avoid going down a path. I've read of many many more algorithms, successful and unsuccessful, than I've ever implemented.
Yup. We've already established that one has to prioritize what to implement. The priority clearly shouldn't always go towards doing something rather than reading what somebody else did. (Children would never learn to write that way.) Instead we prioritize differently at different times, and we try to have lots of feedback between reading and doing, by things like active reading.