Edits don't cause things to head to the close vote queue. Edits on a closed question will sometimes push a question into the reopen queue, but never the close vote queue.
So for some reason, someone must have gone through and manually cast close votes/flags, pushing it into the queue.
Votes shouldn't affect the action you take on the post - if it was highly voted but then determined to be off topic, close it. If it's not close-worthy, leave it open. Each question should be judged on its own - if the standing policy on a specific type of question is that it should be closed, review it and pick the appropriate close reason. If you don't, pick Leave Open.
Unless someone is flooding the Close Votes queue with a mass of on topic questions, I don't think that any moderator action is necessary. There's nothing wrong with going through old questions that should be closed (although some would consider it a waste of time).