Mari-lou A has indicated in the comments that the question was closed because it lacked research. You seem to be assuming that it was closed as a duplicate because it has a "Does this answer your question?..." but if the post notice doesn't actually say:
This question already has answers here:
it wasn't closed as a duplicate (Even the really old questions that don't show which questions they are a duplicate of have that text). Unfortunately, if it was closed for one of the ELU custom reasons, the post notice isn't very informative.
As stated in an answer to New Post Notices are live network-wide:
Unfortunately, with the new post notices, questions closed with custom close reasons now simply say they were closed as off-topic. There’s no explanation of why they're off-topic, and in many cases the questions are about subjects that are entirely topical for the site.
As Laurel pointed out in the comments, if ELU would like more informative close reasons displayed, we would need to come up with the appropriate text for each type of post notice.