It looks like two questions got deleted:
Vim 8.1 cannot be installed with Lua support
Seems like a valid question to me; I manually undeleted it (note it may get cleaned again next week if it doesn't receive an answer/vote).
The key remapping suddenly stop working
This is more tricky, because as it stands there isn't enough information to say anything meaningful. You never replied to D. Ben Knoble last question. I left this question deleted for now. You should update the question with more information so it can be answered.
As to the more general point, it looks like one user gave you a total of 6 downvotes, which caused those two to be automatically deleted. This is a user that "cleans up" a lot of old stuff (using edits, comment flags, votes). You're not being singled out; this user has upvoted and downvoted a lot of content. This user also does this on many different sites, not just this one.
Whatever you may think of the usefulness of systematically cleaning years-old content, for the most part they are using the system as intended. The entire point of SE sites is to build a library of useful and long-lasting information. Voting on older content is part of that; I receive votes on my old questions and answers on a daily basis, which is how the system is intended to work. Downvoting old content is just as much a part of the system as upvoting old content.
That your questions were deleted is unfortunate, but this is how the system works. If a single vote skews your question to be automatically cleaned then perhaps it wasn't a stellar question to start with. Both of your questions are in the "this doesn't work, please help me fix it" category, which I personally don't find very interesting/useful questions (using the formula I described here). I personally wouldn't downvote, but I can see how someone would.
Users' votes are their own, and aside from patterns that clearly don't fit the intended use (e.g. outright abuse) it's not my place as a mod to second-guess people's voting decisions.
It's correct that this pattern is a bit unusual – as DJMcMayhem pointed out in the comments – but from what I can see right now I don't think it warrants any action at this point, although I reserve the right to change my mind on this ;-)