Although I agree with Mad Scientist that self-deleted users shouldn't be contacted with suggestions of continued engagement, I want to address what seems, to me, to be the main motivation to do so in this particular case. I believe that, even if CMs sometimes did contact users who deleted their accounts, it is unlikely that it would be done here. The TL;DR of it all is that, as far as I can tell, the question's deletion didn't contribute to the user's decision to leave Ask Ubuntu, because it took place after they deleted their account.
We shouldn't usually delete people's questions in the first 48 hours after they are asked. This is only reasonable in cases where it is obvious that the question can't or won't be improved enough to potentially warrant reopening, and only 20k users and moderators (and the OP) can cast delete votes in this period. At first glance, it looks like that happened. Combined with how the question was, as Oli said, originally closed as unclear yet answered in comments, this makes it look like the OP was placed in a position where they could neither know why their question was closed nor meaningfully attempt to improve it.
However, unless there is a bug in the system that causes events to be reported incorrectly in post timelines, the question was deleted only after, and as an automatic result of, the OP's decision to delete their account. The Community♦ bot deleted the post, and gave "User 967514 deleted" as the reason. Therefore, the deletion of the question did not, at any point, influence the OP in deciding whether or not to delete their Ask Ubuntu account.
Account deletion does not result in the deletion of most posts. However, there are a few situations where it does, for some posts. The relevant one in this case is that when a user deletes their account on a site, Community♦ deletes negatively scored questions that have no positively scored answers:
- The system will automatically delete any post with a negative score when its owner's account is deleted, unless the post is a question that has at least one positively-scored answer. (This doesn't apply on meta sites.)
Unlike delete votes cast by human moderators, such votes from Community♦ don't prevent non-moderators from voting to undelete a post. That's why you were able to cast your undelete vote (before a moderator cast a second one, undeleting the question).
What Might Have Been Better
I do not mean to suggest the question was handled well.
Even though I'm inclined to disagree with the original "unclear" close reason (and do disagree with the reasons later given for reclosure), there was certainly a reasonable argument to be made that the question was unclear. The argument could have been stated, in a comment, something like this:
I recommend you edit your question to say why you want this--not to convince us, but to make it easier to figure out what approaches might meet your needs. For example, is something not working? Is there another kernel you want to use? Do you want to know why an OS needs a kernel? This seems like an XY problem. If we close this, you can still edit it; your edit will get it automatically reviewed for possible reopening.
Not being a moderator, I can't view deleted comments, but I don't believe any such comment was ever posted there. Still, even without such an argument made, the close banner for "unclear what you are asking" does give advice on how to improve a question. Although I think it's usually best to comment with concrete and specific recommendations about how to improve unclear questions (unless there is already such a comment), I don't think it's at all unreasonable to cast close votes without commenting.
But what happened here was neither of those cases. The question was commented with what were, in effect, answers. It seems to me that an OP who is new to the Stack Exchange system (and thus perhaps doesn't even strongly grasp the distinction between comments and answers) is made far less likely to realize there's something they can do to improve a question that has been closed and answered in comments than one that has been closed with no comments at all.
I don't want to heap scorn on those who did comment, because they were genuinely trying to help, and maybe did, a little bit; because I've done this sort of thing myself; and most of all because it is not always clear to the author of a comment that it is, in effect, an answer to the question. I also empathize with the desire to avoid posting answers that aren't complete and of high quality, even though we (I think rightly) don't consider that to be a good reason to write a comment instead of an answer.
On the one hand, the material in the comments that were present, if posted in an answer, wouldn't have made as good an answer as yours or WinEunuuchs2Unix's that were posted after the question was undeleted and reopened. On the other hand, such an answer could have been voted on and improved.
I am tempted to mount a flawed argument that such an answer, if upvoted, might even have kept Community♦ from deleting the question, and then to try to connect all this to an emotionally moving, crowd-pleasing pronouncement about the central importance of questions and answers in the Stack Exchange system. But under these particular circumstances, assuming it were still closed and the OP still deleted their account afterwards, I think the question would still have been deleted.