Question deletion is very unusual when the post involved isn't obvious spam or cleaned up automatically by the "Roomba" (typically for closed/downvoted questions without answers once those posts reach a certain age).
The homework policy here is pretty broad, and covers exams and past questions just as much as it covers an assignment someone is presently working on. The key for these questions is that they're allowed only if the poster is explaining thoroughly the attempts they've made and showing what understanding they have. However, homework questions don't get deleted (except by the Roomba clean up), they get closed.
Sometimes, moderator actions have more to do with a user overall than specific content. That puts mods in a tricky situation because by rule we don't discuss interactions with users with third party users, unless those users themselves want a public discussion.
Using user suspensions as an example: if a user is suspended moderators won't post about or explain the reasons on meta; there will be a short, vague sentence on the user's profile, and that's it. If they wish to contest their suspension they can contact the SE staff, or once their own suspension is up they can post on Meta, and at that time moderators can explain their reasoning. Otherwise, it's between the specific user and the mods or SE staff.
If a question itself looks fine, or seems like something that would merely be closed rather than deleted, you can assume there's some other underlying reason.
I apologize that your efforts towards writing an answer were interrupted in this case - that's of course not anyone's intent nor desire and I sympathize as I've found myself in exactly your frustrating situation on a few occasions.
