In general, the mere fact that a question is about emoticons does not warrant closure.
The way emoticons are used makes them part of our language. You can look at usage, track etymology, and assess how well-known or obscure a particular emoticon is. In fact, there are plenty of linguists researching emoticons already.
Oxford Dictionaries Word of the Year 2015 was 😂.
Additionally, emoticon usage is impacted by the language of the speaker:
- While geography matters in determining the emoticon
style, language has a higher impact. In the Philippines and
Indonesia, where English is in common usage along with local languages, users utilized horizontal style emoticons as in predominantly English speaking countries.
- European users were multi-cultural in terms of emoticon
usage with both vertical and horizontal styles being employed
Emoticon Style: Interpreting Differences in Emoticons Across Cultures
The fact that some parts of emoticon usage are shared with other languages doesn't actually matter. English gets most of its words from other languages already (what are we going to do, ban questions that happen to be about words that are cognates?).
Of course, this doesn't mean certain emoticon questions shouldn't be closed, like any other question, when they fail to meet certain standards. The question "what does this emoticon mean" is something better solved with basic search skills, and should be closed as general reference.
For the particular question you're asking about, it was reasonable to close as unclear. I looked around; there are a few style guides that mention emoticons, but they all fail to go into more detail than how (in)frequently emoticons should be used. It's not clear what sort of style guide they were expecting the answer to come from. It fits under some of the other options, as well, depending on how you look at it.
Since there's no standard way to use emoticons in English, answers will tend to be opinions ("this is how I do it"), or long lists of many different ways (too broad).