This question already has an answer here:
The Help Center says:
For licensing, moral, and procedural reasons, we cannot review code written by other programmers.
Can somebody explain what is immoral about reviewing someone else's code?
If Person A posts their code, we're allowed to review that, but if Person B posts Person A's code, we can't? The goal in reviewing after all isn't to shame another person for writing subpar code, but to recommend ways of improving their code.
Now because of the licensing and procedural (not sure what that means exactly) reasons, I'm not suggesting that we allow posting other people's code, but just that we remove the word "moral" from the list of reasons.