Note: This question is not intended to be opinion-based, it's intended for clarification of what is "allowed" (I know there are no rules) as a reason for down-voting.
A complete question has these three main parts:
The introduction of the code, containing information about what the code does.
The code itself.
Specific things that the OP would like help on.
That being said, I don't really see how it's possible to down-vote a post; there is nothing to down-vote.
You can't down-vote the because of the introduction of the code; that is merely stating the facts about the code.
You can't down-vote because of the code itself; the point of this site is to fix bad code.
You can't down-vote what the OP would like for help; they are simply stating what points in their code they think are not good.
(Yes, I know; there are some exceptions to these. For example, troll posts).
That being pointed out, I don't see any possible reason for down-voting a post.
This was created because, the other day, someone in chat said something along the lines of this:
People often assign down-vote to off-topic and up-vote to on-topic.