There's a few reasons why these identify-this-movie and identify-this-tv-show tend to get frequently downvoted:
Poor formatting/grammar
I edited the question you linked to. Before I edited it, it looked like this:
theres this movie i remember from my childhood about a city of
monsters living underground and the monsters went up to the human
city/world through a hole at night to steal food from the peoples
houses and there was a teenage monster who mets a teenage human and
they become friends. theres a scene I remember when the monsters took
baths filled with mud and the monster mom had 3 boobs (weird i know)
but thats all i remember. HELP i want to remember the name
It's certainly not unanswerable, or unreadable, but it's a poorly formatted question. There is a single sentence, with no grammar or capitalisation and it includes unnecessary text (HELP i want to remember the name).
If the odd question being posted was like this, people wouldn't mind so much - but I have to edit almost all identify questions to make them somewhat more readable and to remove unnecessary text.
Obviously, if anyone reads the question before the edits they are likely to downvote it for its presentation (after all, if someone can't be bothered to do some basic formatting, why should we answer their question)?
And even if they read it after the edit, they may still feel the description isn't clear enough or the question is so poor it doesn't deserve votes.
Downvoted before edits
Similar to the above, some questions have very little detail when they are posted, and despite being changed later have already been downvoted based on this little information. Take this question. It originally read:
I'm trying to find the name of this movie for my dad. I haven't seen
it myself, and all he remembers is that near the beginning and older
woman is talking to a young boy and then she unexpectedly gets hit by
a bus. Google is failing me. Any ideas?
That's a pretty poor question. It has since been updated with some more information, but it still has a score of -4. I don't see this as a bad thing though. We don't want to encourage poor questions, we want people to research and post better questions in the first place.
Helpful to others
The Stack Exchange doesn't just exist to help a questioner, but to help future questioners as well. Many identify-this-movie and identify-this-tv-show questions have almost no information whatsoever - and so even if an answer could be provided to the question, it's unlikely to help any future user to the site.
Here's a current example of one such question, which is currently still open:
I remember this scene where there were men with a black eye mask, they
were wearing a hat, black clothes and they were fighting on the train
with weapons, then the train fell from above...
It's not completely unanswerable, but it's exceptionally vague. I downvoted this and voted to close it. It's not because I don't think an answer could ever be found, but because I think the question is of no use to anyone other than the OP - I don't believe any future users would benefit from it.
Dislike of ident questions
A quick browse of the Meta will show that identify-this-movie and identify-this-tv-show are fairly controversial here. Many people (myself included) would like to ban them totally. There are a variety of reasons why, which are all covered elsewhere and would take a while to explain in depth, but in summary there's a strong argument that the presence of ident questions reduces the quality of other questions and harms the sites.
Our identify identify-this-movie and identify-this-tv-show questions continue to rise, and there's a real worry it pushes movie fanatics away due to a front page that is constantly overloaded with poor quality ident questions.
Given this, many people will downvote these questions unless they contain a substantial amount of detail, such as this question, or this question.
Lack of interest
We don't just upvote correct answers, and downvote incorrect answers. We also upvote answers that we are interested in and which help us, and downvote answers we disagree with.
Part of the problem with identify-this-movie and identify-this-tv-show questions is an all round lack of interest in the actual question.
Take a question like this: Asian movie where a girl commits suicide jumping off the window (art cinema)
It doesn't sound familiar to me and I've little interest in it. Aside from checking if the question itself needed to be edited to make the formatting clearer (it didn't), I had no interest in the question and no interest in the answers.
That meant that I ignored the question (didn't upvote or downvote) and ignored the answers. However, on other similar questions which have poor answers, I'm more liable to ignore the question, ignore the other answers and downvote the poor answer - as even without an interest in the question, a poor answer stands out very clearly and so is easy to downvote.
Inability to check correctness of answers
Another issue with identify-this-movie and identify-this-tv-show questions is knowing whether to upvote answers or not.
Many answers are very simplistic and I've noticed people often hold off on upvoting them too much unless they include lots of detail or the OP accepts them. Take this question for example:
I vaguely remember a movie with thieves that break into a mansion but
it belongs to their boss. They didn't know at the time when they broke
in. They broke in and went to a basement where they had to break a
wall and get gold or money from inside a wall. Then they got locked in
when the bad guy (they helped get the gold for) set off the alarm and
killed the guard dog. In the end I think they had to get all the gold
back.
It has two answers:
An answer the OP said was correct (but which the OP left unaccepted):
Sounds a lot like The Hangover 3, in which they were tricked into
stealing gold from a mansion and then threatened if they could not
steal it back.
https://en.m.wikipedia.org/wiki/The_Hangover_Part_III
A downvoted answer:
I guess, it is Tower Heist (2011) with Ben Stiller.
Both are pretty sparse on details. Whilst The Hangover answer was what the OP was after, the answer describes a scene many films could have. So should voters cast their vote based on whether they think the film matches what the OP is after, or wait for the OP to confirm it's what they're after.
Obviously, the answer is the former. We cast our votes based on our opinions. But with such short answers given, for me to know if either of those answers could be correct, I have to go and research the movie in question to find out. But I'm reading an answer - I have zero interest in researching to see if it's correct. The answer should provide all the evidence necessary to show it is correct (see @Walt for examples of this sort of answer). Therefore, for that question, I downvoted the second answer and simply ignored the first.
Conclusion
There are many, many reasons why the questions and answers don't get the love some people feel they deserve as opposed to a single, specific reason.
I feel the downvotes are obvious:
- Poor formatting/grammar
- Lack of information
- Little help to future users
- Dislike of ident questions
However, another issue that compounds this and make the downvotes more clear is the lack of upvotes on the questions fora few reasons:
- Dislike of ident questions
- Lack of interest in question
- Inability to check "correctness" of answer in relation to OP's ask
identify-this-moviequestions are always downvoted even if perfectly valid?