Short version
Should we up- or down-vote on questions that we encounter through the close votes review queue? And should voting be available to us through the close vote queue's UI?
Long version
Most of the questions that I encounter on the close votes review queue are there because they're crap. There's the odd well-considered, well-written question that's there because it's a duplicate, or needs to be migrated to another site, but the things that get there because of the Unclear what you're asking, Demonstrate minimal understanding or Describe the specific problem close reasons are almost invariably terrible. As it happens, I usually filter down to the Unclear and Off-topic close reasons when reviewing, so the majority of the questions I see would deserve to be downvoted if they were to stay open in their present form.
On the one hand, voting on these questions when I see them ought to be a good thing for the same reasons that voting in any circumstances are a good thing. On the other hand, given that much of the point of changing the "Closed" notice to an "On hold" notice was to encourage closed questions to be edited into a better state and reopened, I can see how it might be undesirable for close vote reviewers to downvote the crap they see. If I vote to close a question, and it is later improved, other members of the community can reverse the closing. If I downvote a question that is later improved, my action can only be reversed by me. For the mostly newly-posted questions that I stumble upon via the review queue and then never look at again, perhaps downvoting is, on net, harmful - it heaps punishment that will never be revoked onto question askers who we're supposedly encouraging to edit and improve their questions.
The fact that I can't downvote directly from the close votes review screen - despite the fact that it's a constant stream of downvote-worthy questions - seems to suggest that downvoting in these circumstances is discouraged. Yet Shog9♦'s answer explaining why up and down voting isn't possible from most review screens makes no special mention of the close votes queue. And in the comments below his answer, the following exchange takes place:
animuson♦:
I think the close votes task should allow voting. Upvoting a downvoted question which has close votes is a good way to save a question which may not be close-worthy or has been edited after those votes were received. As well, downvoting a question is a good way to get it closed faster.
KatieK:
Please let me vote while in the Close Vote review queue. It's the job of the honeypots to catch bad reviews. The CV queue is so crowded that I always filter it down to areas of my expertise anyway. Sometimes the CV queue shows me a post deserves a downvote (which may get it automatically deleted later on). And sometimes it shows me a post that deserves an upvote because it's been improved (added code, clarified question, etc).
Shog9♦:
If you have a special interest in a particular question, break out of /review and do whatever you like, @KatieK: vote, flag, answer, etc.
So to sum up, I can see reasonable arguments both for and against voting on questions I see in the close votes queue, we have a UI that seems designed specifically to discourage it, we have moderator animuson♦ encouraging voting on questions from the close votes queue and saying that he disagrees with that UI, and we have StackExchange exployee Shog9♦ seemingly defending the UI not allowing voting but simultaneously encouraging voting anyway (but perhaps only in special circumstances).
I feel like I'm getting mixed signals. Should I downvote crap when I see it in the close votes queue, or not?