Why can one continue to downvote a closed question?

Question

Once a question has been CLOSED, it seems that users should not be able to either UP or DOWN vote the question. To do otherwise seems a little unfair in the downvoting case. Especially since apparently you must now wait for 2 days for the author to delete a question.

It seems that this should be fixed.

Answer 1

I thought I'd recently seen the auto-delete criteria posted here, but I can't find it now...

I fairly frequently downvote closed, downvoted questions just to be sure they get auto-deleted. Since I can never remember exactly what the rules are for the auto-deletion, if something is -1 with no activity, I'll often make it -2 just to be sure.

According to the FAQ post on Meta.SO about deletion, my habit of adding another -1 just to be sure a closed question gets deleted isn't necessary:

• The system will automatically delete unlocked, unanswered questions that have negative score after 30 days.
• The system will automatically delete unlocked, unanswered questions with score of zero (or one if the owner is deleted), fewer than 1.5 views per day on average, and fewer than two comments after a 365 days.
• The system will automatically delete any question (and its answers) or answer with a score less than 0 when its owner's account is deleted.
• The system will automatically delete questions migrated to other sites after 30 days.

Answer 2

As a general rule I don't downvote closed questions but I will do so if I see any reopen votes cast on a question that I think should remain closed, just to highlight the fact that it's a bad question.

Answer 3

I partially agree with the sentiment here (once it's closed there's no reason to keep piling on downvotes just because they're free), but I think that's a human problem - not a technical one.

I believe the reasoning behind allowing votes on closed questions is that the author can improve their question, thus making it worthy of re-opening (or the question may have been closed in error).
In those cases the upvotes a question may earn can be an indication that we should consider re-opening the question. Also if a question is edited people can change their votes on the question while it's still closed (which is particularly important for people who can upvote/downvote but can't yet vote to close/reopen).

Questions can also be locked, which prevents voting (or any other changes), but that's a moderator action (and one we tend to use with at least a little restraint since it means the OP can't fix a bad question)