I was thinking in situations where a coworker might send me something to review, and I might have thought "hmm, I wouldn't have done it like that, but this is a great way to do it too". Also, a good source of teachable code is to participate in a programming contest, and then review the repositories of the teams who scored better than me after the contest.

I agree that if I don't already know how to implement something, seeing a solution before trying it myself is not great, that's like skipping the homework exercises and copying straight from the answer books.

This is why tutorials in programming don't really teach much because you get the finished version. Not all the wrong steps that were taken, why they failed, what else was tried.

These steps are what help you solve other issues in the future.