I don’t completely disagree, just like 90%. Junior developers typically aren’t taught the design patterns in the first place so they dig deeper holes rather than immediately recognizing that they need to refactor, pull out an interface and decorate/delegate/etc.

I’m also going to point out that this is a data structures course that I’m teaching, so extensibility and composability are paramount concerns because the interfaces we implement are at the heart of almost everything else in an application.