There are people out there who don't like homework-type questions. They will probably down-vote such questions, even if you observe that it is generally well received by the community. That is how the system works.
Voting is nothing personal, it is about the content. Don't take (make) it personal.
There is no way to find out who voted how; and there shouldn't be. Users are encouraged to leave a comment when down-voting, but it is not mandatory.
I enjoy being able to down-vote posts I don't care for without worrying about retaliation. And I really enjoy being able to leave honest comments without worrying that they'll be justifiably interpreted as evidence that I've down-voted. I would not like to see the two systems linked. – Shog9♦ Jun 28 '09 at 19:36
This system has (more or less and with a few bumps) worked for quite some time now. There have been multiple (attempts at) changes over the years. I welcome you to explore meta.se and perhaps post your suggestions there.
Over the time there also have been multiple posts of users who are unhappy with down-votes. Most of them use language which is not really appreciative of our be nice policy. Maybe you would like to check your post, if there was any way to improve upon its wording.
Please always keep in mind that each and everyone is offering their free time on this site. Treat people with respect, do what you would expect other users to do, and view posts objectively as content and not a s opinions. If you're nice you will be helped and welcomed, if you're rubbing users the wrong way, you will be ignored.