It should be closed as phrased, but a very slight modification can salvage it
I tend to agree that the "Unclear" doesn't fit but...
It could be closed for either the "Primarily opinion-based" or "Questions asking for the truth or validity of a particular doctrine or belief (aka Truth Questions), and questions asking Is X a Sin? are not a good fit for our site, due to their subjective nature, and the vast number of possible Christian opinions on such topics. See: We can't handle the truth"
This all hinges on one statement in your question above:
I also feel that the question is not primarily opinion-based since
answers could be backed up by Scripture
That statement, odd as it may seem, is one we've had to deal with on the site in a way that seems at odds with basic "Christian" way of thinking – particularly for those of us (that includes me, personally) who believe that the Bible, not man's opinion, is the ultimate source of Truth.
The problem is that there are plenty of doctrines/beliefs out there that are not only different, but wholly opposite, and all of them can be "backed up by Scripture". The various groups that adhere to these wildly different beliefs can usually point to Scripture for the source of their teachings, they just point to different verses, and/or interpret the verses differently. (Of course, there are also completely extra-Biblical teachings; I'm ignoring those for now.)
A classic example is Calvinism and Arminianism
A couple of relevant links to help rephrase that issue are:
Your sentence goes on to say...
or perhaps by a citation from the Catechism of the Catholic Church
Now you're onto something. You're looking for a specific, authoritative documented teaching of a specific group. The only problem is that nowhere in the title of the question or in the question body itself do you say that you're looking for a Catholic teaching. The wording is phrased as if you're asking for the Truth. It's only if you look at the tags that we can tell that you've got any leaning toward an established denominational or doctrinal teaching.
Now I realize the votes aren't overwhelming, but we did address the question of whether tagging a question is sufficient to scope the question, and the answer with the most votes is "no". The main reason for this was:
The reason being that your average newcomer to the site is not going
to pick up on that little nuance. Experience SE members, sure. We get
tagging. your average new visitor? Probably not.
When someone who doesn't know to look at tags, or get the nuances will look at your question as a "Truth" question.
The simple fix:
The Simple fix is to adjust the title and preferably the body of the question to start with something like "According to Catholic teaching...", so that it's clear that you're looking for a distinct established teaching.
Final note: If it does get closed, you can always flag it to be reopened. Closing a question isn't necessarily permanent. As long as it's been edited properly, a question can get reopened.