A large number of questions on ELL are asking for the meaning of metaphors. Many are from song lyrics or poetry, about which there are a number of meta questions. Some are from literature, most recently:
And sometimes they come from the news media.
I wonder if these should really be considered specific to the English language? The meaning of a metaphor is mostly derived from the concepts represented in the words, not the particular language used. If you do a literal translation of the metaphor into another language, it would usually have the same meaning (although that doesn't mean the same phrase would necessarily be used by a native of the other language).
This is different from an idiom, whose meaning is not necessarily determined from the literal meanings of the words, and a word-for-word translation would not make sense. Which is why questions about idioms are perfectly on-topic.
It seems to me that many people post these questions in lieu of trying to think imaginatively about the phrase they've heard/read. If they don't immediately understand the phrase, they seem to assume it's an idiom and give up. I'd like to encourage them to make more effort first.
Some of the questions do show a little attempt to discern the meaning, they ask "Does phrase mean definition?", and perhaps these should be acceptable. But questions like the above feel like they're just asking us to do their thinking for them.