I agree, in principle. Sometimes, however, the code given as an example in such a case as you describe is riddled with myriad incorrect assumptions, out-and-out coding errors, misused idioms and common mistakes and is so far from my own coding style that after addressing all the above, there's no longer any question to answer.

My own approach to situations like this is sometimes to simply write a completely new code snippet which accomplishes what I estimate was the original goal, without so much as the slightest resemblance to the original, along with an explanation to the effect of, "here's how I might try to do this."

And sometimes (here on Perl Monks, anyway), I leave it to those more adept than I.

dmm