The recent question Need help with love has received an upvote. I am tired of trying to preserve the credibility of the site by reverse-voting such perverse voting (which happens far too frequently). Is there some way to deal with anonymous members voting in a way so detrimental to the site?
No, there's nothing anyone can do about it. All upvotes are anonymous; not even moderators can see them normally. I wouldn't worry about the credibility of the site; people who have been on Stack Exchange for a while are all aware that voting has an element of noise. A single upvote will not preserve the question from deletion.
If it's a single upvote, don't worry about it. Mistakes happen.
I think the question should not be about the upvote, but about the OP. It's been removed, appropriately. That takes care of its baggage as well.
It appears the mechanism in place to deal with such low quality questions is working. If anything, I'm guessing questions with votes are probably seen more and therefore more prone to being eliminated if they're in need of it. So the voting may actually be part of the solution rather than a problem in itself.
I generally agree with @sumelic's answer, but I don't agree with "there's nothing anyone can do about it." There is no problem that has no solution. I am a very aggressive voter with 3,247 upvotes and 2,891 downvotes. When I saw a comment to a moderation election post which raised the issue of upvote/downvote ratio of a certain candidate, it was really hilarious. Some users seem to misunderstand the philosophy behind downvoting, believing it conflicts automatically with a be nice policy. Well, downvotes help the site clean up its mess, keep the quality and could lead to a more useful post encouraging an edit.
I kept mentioning "upvoting privilage should not be given to users with 101 association bonus" on various Meta SE posts such as How about creating "Most Recommended Question (MRQ)" list.
I also believe it is time SE considered cancelling the upvoting privilege to 101 (association bonus) reputation users. They sometimes (I am guilty, too) go to some sites (especially new) and vote without knowing well whether a question or answer is well-researched and really helpful.
I am not saying that particular upvote was cast by a user with an association bonus. When the number of upvotes goes up beyond reasonable level, I suspect many of them are cast by them. "Giving them the privilege to upvote so that the OP can receive reputation points, but don't count their upvotes on the post" could be a reasonable solution.
I don't think you are talking only about that execrable question. If there are posts that you think have some issues, you can post the link in ELU Reviewers chat room.
What ELU needs now is more downvoters who can downvote a post that doesn't show research effort and when it is unclear and not helpful. Their downvotes will off-set those blind upvotes down the road.