https://stackoverflow.com/questions/7304008/a-language-like-a-typed-php
That question of mine was closed a long time ago (relatively, to me at least). However, from time to time I still get downvotes for it. That got me thinking: is there any reason to still downvote closed questions?
You'll notice that you earn 'interest' on your old questions and answers. As time passes and links to information build up, people will find your posts through searching. At that point, what you wrote will either help them or it won't. Sometimes, older posts earn negative interest.
Closed questions are still eligible for voting for a very good reason, they're still visible. We want people casting votes based purely on the usefulness, accuracy and quality of a post. The fact that the title says [closed] shouldn't influence that.
I like questions like the one you wrote, they just don't fit well in the Q&A format that is Stack Overflow. People are probably reacting to that while turning your question up in a search when researching a specific problem.
Closed questions naturally decay over time, as high rep users cast deletion votes. If you're really concerned that the question isn't really useful and want to speed that process along, flag it for moderator attention. Unfortunately, you can't immediately delete it yourself, the question has up-voted answers. It will take several additional votes to delete before it actually happens, or a binding moderator vote.
But, remember - the chief concern here is the usefulness of the question in question, not the cost of the down votes.
Given that the "auto delete of closed questions" only delete closed quesions with a given number of down votes (someone else can find the details!), then downvoting a closed question helps it to be deleted.
As Anthony has pointed out to you, old (even closed) questions can gather both up votes and down votes. A question can be closed for a multitude of reasons but it may still be a question that people visit and possibly get some help from, hence people still continuing to vote on it.
However you are in a position to do something about it:
I looked at your question, and IMVHO it adds no lasting value to the site, so to help put you out of your misery I have cast a delete vote for you. Once two more people have also cast delete votes it will be deleted, and will no longer gather down votes.
*I'm not sure if there are rules preventing a lower rep user from deleting their own post once it has answers.
