- A question that invites opinion is asked.
- A few people give answers, one of them is a new user
- The question is closed before any voting
- The new user's answer appears in review.
Comment I don't think it's worth asking the new user to improve their answer - it would effectively be asking them to add debate to their opinion. I can't think of much to say other than politely explain the situation to them, advising them not to answer (or ask) subjective questions in the future.
Upvote I shouldn't upvote the new user's answer - I don't want to join this debate. This debate should stop (and although I don't feel strongly, I probably wouldn't choose this answer as the best). Upvoting all the answers is fair but inappropriate.
DownVote I don't think I should punish the new user with a downvote for honestly trying to help, so a downvote is unfair.
Don't know simply leaves the problem in the queue for someone else, so this can't be the permanent advice to all reviewers.