Referring to the question here: What does $|λ,μ\rangle$ mean in Dirac notation?
Recently I've noticed a lot of questions closed or downvoted when the answer is obvious to someone who already knows the subject well, or when the answer would just be very short and uninvolved. However, I think that many of these questions can cause a learner to stumble for a long time (certainly I've lost a lot of time on things myself that only became "obvious" in hindsight).
In this case, the reason given for closure
Homework-like questions and check-my-work questions are considered off-topic here
clearly does not apply to the question; the context is confusion about a learning video, which is neither homework nor work of OP. The score is negative, and also there are no comments on why it was closed or downvoted. The user, with 11 reputation, is not experienced with stackexchange.
I think we could greatly improve the site by helping to teach new members like this if there is something wrong with their question, rather than silently closing the question. This can simply be done by focusing close votes on quality, not quantity, when it comes to close/downvoting, by explaining why.
In either case, it seems like this question may have been closed for no good reason, but I'm not intimately familiar with policy here; under which criteria was the answer closed? Is there ever justification for closing a comprehensible question without any comment to an OP who is new to the site? I can find some gripes with the post myself (could be formatted rather than / in addition to screenshotting, could explain better what $\Psi_{\lambda, \mu}$ is) but it was clear enough for me to correctly answer what was being asked without asking for further clarification, and I feel like it would be more productive to focus on explaining to such new users how to improve their question, rather than silently removing them.