This happens out of inertia. Once a question has entered the close vote review queue, the default action for many a reviewer is apparently to agree with the initial assessment of a fellow member. If the early part of the comment chain does not look convincing, it is a bit too easy to overlook later developments.
BUT. As we just saw, the community is self-correcting in this sense. Which brings me to a suggestion:
When we explain to a newbie what is wrong with their question - typically in a comment - we should also explain that the improvement to the question may come too late (for the purposes of avoiding that fifth vote to put on hold). But also that the improvement may later lead to the question getting reopened.
I try to write something in this spirit on those occasions, when my suggestion for improvement will necessitate the OP to spend some time thinking about the question. A typical scenario is that I arrive at the scene with 3 or 4 close votes already in place. If I at that point advice the OP to work out a simple case, and add that to the question, it doesn't take Yogi Berra level foresight to look ahead, and divine that the question will be put on hold before the OP has had time to work out the answer to my suggestion and edit the post.
So the other message that should be given is:
Getting a question "put on hold" is not
a death sentence a final judgement - neither on the poster nor on the post. It just means that the question is in dire need of improvement.
The newbies should be explained this in such a way that they are left with the impression that this was just another new kid on the block faux pas, and also an opportunity to learn the site norms.
I might try and edit the relevant comment templates to reflect these ideas, but it may be better that a native speaker steps up to the plate. My sentence structure has a tendency to become overly convoluted.
So my answer to Gerry's question would be:
The new user should improve the question as instructed. And then wait for the due process to go through. Patience.